Zitat Update #15 for Peregrine Mission One Press Release 01 | 12 | 24
Peregrine remains operational at about 238,000 miles from Earth, which means that we have reached lunar distance! As we posted in Update #10, the Moon is not where the spacecraft is now (see graphic). Our original trajectory had us arriving at the Moon on day 15 post launch. Our propellant estimates currently have us running out of fuel before this 15-day mark — however, our engineers are still optimistic about extending Peregrine’s life expectancy.
On Thursday, January 18, 2024, at NOON ET, Astrobotic is hosting a teleconference with NASA for major mission updates and will be streamed on select NASA channels. With Peregrine operating in a stable configuration and a teleconference imminent, we will post an update tomorrow, but will be slowing down our update cadence for now. Thank you again for the words of support we’ve received for our team.
Zitat Peregrine moon lander heads back toward Earth and should burn up in the atmosphere January 14, 20242:06 PM ET
The lunar lander whose much-anticipated mission was stymied last week due to a propellant leak is now expected to fly back toward Earth and burn up in the atmosphere.
Zitat Update #16 for Peregrine Mission One Press Release 01 | 13 | 24
Over the last week, Astrobotic’s Mission Control Center has been tracking Peregrine’s trajectory. Our analysis effort has been challenging due to the propellant leak, which has been adding uncertainty to predictions of the vehicle’s trajectory. Our latest assessment now shows the spacecraft is on a path towards Earth, where it will likely burn up in the Earth’s atmosphere. The team is currently assessing options and we will update as soon as we are able.
The propellant leak has slowed considerably to the point where it is no longer the team’s top priority. A reminder that a soft landing on the Moon is not possible. We have now been operating in space for 5 days and 8 hours and are about 242,000 miles from Earth.
Zitat Update #17 for Peregrine Mission One Press Release 01 | 15 | 24
For 16 years, Astrobotic has been dedicated to making the Moon accessible to the world. The responsible preservation of the cislunar space environment for all is top of mind as we complete this mission. Since the Peregrine lunar lander’s anomaly occurred 6 days ago, we have been evaluating how best to safely end the spacecraft’s mission to protect satellites in Earth orbit as well as ensure we do not create debris in cislunar space.
Working with NASA, we received inputs from the space community and the U.S. Government on the most safe and responsible course of action to end Peregrine’s mission. The recommendation we have received is to let the spacecraft burn up during re-entry in Earth’s atmosphere. Since this is a commercial mission, the final decision of Peregrine’s final flight path is in our hands. Ultimately, we must balance our own desire to extend Peregrine’s life, operate payloads, and learn more about the spacecraft, with the risk that our damaged spacecraft could cause a problem in cislunar space. As such, we have made the difficult decision to maintain the current spacecraft’s trajectory to re-enter the Earth’s atmosphere. By responsibly ending Peregrine’s mission, we are doing our part to preserve the future of cislunar space for all.
Despite the propulsion system issue, the Astrobotic Mission Team has worked tirelessly to stabilize the vehicle, turn on all active payloads, and enable the collection of payload data. The spacecraft has been operating in space for 6 days and 16 hours, and Peregrine continues to leak propellant, but now at a very slow rate. Yesterday afternoon, we test fired one of the main engines for the first time. We achieved a 200 millisecond burn and acquired data that indicated Peregrine could have main engine propulsive capability. However, due to the anomaly, the fuel to oxidizer ratio is well outside of the normal operating range of the main engines making long controlled burns impossible. The team projects that the spacecraft has enough remaining propellant to maintain sun pointing and perform small maneuvers.
Astrobotic designed and built hardware, avionics, software, and system architectures that have all performed as expected in space. All payloads designed to power on and communicate did so, and even achieved science objectives. While we believe it is possible for the spacecraft to operate for several more weeks and could potentially have raised the orbit to miss the Earth, we must take into consideration the anomalous state of the propulsion system and utilize the vehicle’s onboard capability to end the mission responsibly and safely.
Peregrine will soon return to Earth’s atmosphere and the vehicle is now about 234,000 miles away. We are working with NASA to continue updating and evaluating the controlled re-entry path of Peregrine. We do not believe Peregrine’s re-entry poses safety risks, and the spacecraft will burn up in Earth’s atmosphere. We are validating this through analyses in collaboration with the U.S. Government. We will continue to operate the spacecraft and provide status updates through the end of the mission.
“I am so proud of what our team has accomplished with this mission. It is a great honor to witness firsthand the heroic efforts of our mission control team overcoming enormous challenges to recover and operate the spacecraft after Monday’s propulsion anomaly. I look forward to sharing these, and more remarkable stories, after the mission concludes on January 18. This mission has already taught us so much and has given me great confidence that our next mission to the Moon will achieve a soft landing,” said Astrobotic CEO, John Thornton.
Zitat Update #18 for Peregrine Mission One Press Release 01 | 15 | 24
Peregrine has been operational in space for 7 days and 13 hours. The spacecraft continues to be responsive, operational, and stable, and remains on its previously reported trajectory toward Earth’s atmosphere. The propellant leak caused by the anomaly has practically stopped. The team continues to work with NASA and U.S. Government agencies to assess the final trajectory path in which the vehicle is expected to burn up. Peregrine is now about 218,000 miles away from Earth.
This photo was taken in space today, with a camera on one of Peregrine’s payload decks. This is the same camera view as the first photo we received from the spacecraft on January 8, 2024.
Zitat Update #19 for Peregrine Mission One Press Release 01 | 17 | 24
The Peregrine spacecraft continues to be responsive and stable and has been operational in space for 8 days and 16 hours. The mission team is continuously monitoring the spacecraft’s trajectory back to Earth. We remain in contact with our U.S. Government partners to ensure as safe a re-entry path as possible. As a reminder, Peregrine reached apogee on Saturday and is now about 183,000 miles from Earth.
Zitat UPDATE #20 FOR PEREGRINE MISSION ONE PRESS RELEASE01 | 17 | 24
Astrobotic has positioned the Peregrine spacecraft for a safe, controlled re-entry to Earth over a remote area of the South Pacific. The team has been continuously monitoring our re-entry analysis with NASA, which indicates a re-entry path over the indicated area below, with no anticipated hazards. A safe re-entry is our top priority, so the team developed a two-step maneuver to move the spacecraft and change its projected trajectory.
The first step required a main engine burn. Due to the propulsion anomaly, it was impossible to operate the main engines normally. As such, we developed a plan to fire the main engines with a series of very short burns. We conducted a test burn of all five main engines. Each pulse was spaced out to avoid overheating, allowing our mission control team to monitor results and the spacecraft’s status after every burn. Following this, we performed a series of 23 small main engine burns.
Secondly, we adjusted the spacecraft’s attitude so the force induced by the leaking propellant shifted us towards the South Pacific Ocean. The result of these two maneuvers is the ellipse in the graphic shown.
The procedures the team executed were to minimize the risk of debris reaching land. Astrobotic continues to work closely with NASA and other relevant government authorities to keep everyone informed and to solicit feedback as appropriate.
Peregrine has been operating in space for 9 days and 16 hours. It is 139,000 miles (223,700 km) from Earth. We expect re-entry to occur at approximately 4pm Thursday, January 18 (US Eastern time).
As re-entry is now targeted for Thursday, we are moving our previously scheduled media telecon to Friday, January 19 at 1pm (US Eastern time) to provide a comprehensive mission update.
Peregrine Re-Entry Trajectory as of 17 Jan 4:30 p.m. US EST Center Lon: 176.594 deg Center Lat: -23.087 deg
EST ≙ MEZ-6; für uns also 22:30.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat Watch Japan attempt to ace its 1st-ever moon landing on Jan. 19 with this free livestream (video)
The nation's SLIM lunar lander will try to touch down at around 10:20 a.m. ET on Friday (Jan. 19).
Japan's robotic SLIM spacecraft will attempt to pull off the nation's first-ever successful moon landing on Friday morning (Jan. 19), and you can watch the action live.
SLIM (short for "Smart Lander for Investigating Moon") is scheduled to begin its touchdown operations Friday at 10 a.m. EST (1500 GMT; midnight on Jan. 20 Japan time), with a soft landing on the moon occurring 20 minutes later, if all goes according to plan.
You can watch it live here at Space.com, courtesy of the Japan Aerospace Exploration Agency, or directly via JAXA. Coverage will begin at 9 a.m. EST (1400 GMT; 11 p.m. Japan time).
Zitat The Peregrine lunar lander is believed to have reentered Earth’s atmosphere on Thursday, Jan. 18, according to Astrobotic. The company has been providing continuous insights into the mission, giving the public the opportunity to see the challenges of spaceflight with ongoing detail.
Astrobotic said any debris from the lander was expected to splash down in the South Pacific Ocean around 4:04 p.m. EST (2104 UTC) around longitude of 176.594 degrees West and a latitude of 23.087 degrees South, which is south of Fiji. The company said it lost telemetry from the spacecraft as expected at 3:50 p.m. EST (2050 UTC).
NASA and Astrobotic are set to host a teleconference regarding this first CLPS mission on Friday, Jan. 19, at 1 p.m. EST (1800 UTC).
Zitat "While this indicates the vehicle completed its controlled re-entry over open water in the South Pacific at 4:04 p.m. EST, we await independent confirmation from government entities," the company wrote in an update that it posted to the social media site at around 8 p.m. EST on Thursday (0100 GMT on Friday, Jan. 19).
Was mich zu meiner Eingangs gestellten Frage zurückbringt: wenn über dem Südpazifik eine Raumsonde verglüht und niemand die Rauchspur sieht: gibt es sie dann?
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
16:12 MEZ. Höhe 15 km über der Mondoberfläche. 16:13. 3. Bremszündung. 16:17. Vertikaler Landeabstieg begonnen. 16:20. 2. Schwebestopp in 50 m Höhe zum Scannen des Geländes. 16:21. "MLM" - Landung. Warten auf Telemtriedaten des Landers.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
16:30. 10 Minuten nach der Landung. Noch kein Funksignal vom Lander.
Zitat SLS (Space Launch System)@ScottLikesSLS The final descent seemed to be far too fast, and if the Position data is right, it looks like it quickly tried to do the flip while it was still coming in and maybe over did it, hopefully that datas wrong as the solar panel will not have a fun time like that 4:28 PM · Jan 19, 2024
"...it quickly tried to do the flip while it was still coming in and maybe over did it..." Umfallende Raketen scheinen gerade schwer angesagt zu sein.
PS.
Zitat Scott Manley@DJSnM So my take is that it landed and rolled. Why? * Landing too fast * Landing and not shutting down engines immediately * landing with too much lateral velocity. Angular momentum makes things roll futher in low lunar gravity.
If the orientation can be trusted then SLIM is facing its solar panels westwards meaning they have no sunlight right now, but, they will be illuminated in a few days and some science may be possible. I also need to look to see what instruments may have been impacted by a roll like this.
Needless to say, with power running down the engineers have more important things to do than a press conference right now. 5:04 PM · Jan 19, 2024
Aktuell Preesekonferenz der JAXA zum Stand der Mission. Die bogien Analyse scheint zuzutrefffen: die Landung ist weich erfolgt, aber der Lander ist so gekippt, daß die Solarzellen kein Licht empfangen. Batteriebetreieb sollte für 13 Stunden ausreichen; aber selbst bei völliger Entladung der Batteiren gibt es die Möglichktien, Funksignale zu senden, sobald sich durch den veränderten Sonnenstand die Situation ändert. Während der letzten Pahse des Landabsteigs hat die Sonde eine Reihe von Aufnahmen gemacht, die über die Beschaffenheit/Neigung des Bodens und den Anflugwinkel Aufschluß geben können. Zurzeit sind sämtliche systeme auf Standby geschaltet - allerdings ohne Rückmeldung, um die Batteriedauer möglichst auszudehnen.
PS.
Zitat Chris Bergin - NSF@NASASpaceflight JAXA Update on SLIM: Lander did land, they have comms, but the solar cell is not generating electricity. On battery power. Trying to maximize science. LEV separated as planned but JAXA needs more time to gather data.
It's still sending data, so it was a soft landing. JAXA again says the issue is specific to the solar cell power generation. No mention of a roll or any tumble at touchdown, but a reference to the attitude of the lander concerning the solar power generation.
They've shut off some systems, such as the heater, to conserve battery power and extend its lifetime.
The battery will last for "several hours." 6:20 PM · Jan 19, 2024
Zitat Final Update for Peregrine Mission One Press Release 01 | 19 | 24
This afternoon Astrobotic received independent confirmation of Peregrine’s safe, controlled re-entry yesterday in the South Pacific.
Peregrine Mission One has concluded. We look to the future and our next mission to the Moon, Griffin Mission One. All of the hard-earned experience from the past 10 days in space along with the preceding years of designing, building, and testing Peregrine will directly inform Griffin and our future missions.
Peregrine and its payload teams have made a meaningful contribution to our lunar future, and we thank everyone who supported this mission. Courtesy of United Launch Alliance, this video was captured from their Vulcan rocket’s payload fairing.
Momentan stehen die Sterne scheint's wirklich schlecht in Sachen "Eroberung des Weltalls".
Zitat NASA loses contact with Ingenuity Mars helicopter By Mike Wall, published about 8 hours ago
The dropout occurred on Thursday (Jan. 18), during Ingenuity's 72nd Red Planet flight.
NASA's Ingenuity Mars helicopter has gone incommunicado.
Ingenuity's handlers lost contact with the 4-pound (1.8 kilograms) chopper on Thursday (Jan. 18), toward the end of its 72nd flight on Mars.
"Data Ingenuity sent to the Perseverance rover (which acts as a relay between the helicopter and Earth) during the flight indicates it successfully climbed to its assigned maximum altitude of 40 feet (12 meters)," NASA officials wrote in an update on Friday (Jan. 19).
"During its planned descent, communications between the helicopter and rover terminated early, prior to touchdown," they added. "The Ingenuity team is analyzing available data and considering next steps to reestablish communications with the helicopter."
"Perseverance is currently out of line-of-sight with Ingenuity, but the team could consider driving closer for a visual inspection," NASA's Jet Propulsion Laboratory in Southern California, which manages both robots' missions, said via X on Friday.
Ingenuity has stayed aloft for more than 128 minutes and covered a total of 11 miles (17.7 kilometers) during its 72 Mars flights, according to the mission's flight log.
It's unclear at the moment if those numbers will continue to go up. We'll have to wait and see if Ingenuity's handlers can get back in touch with the pioneering chopper, the first vehicle ever to explore the skies of a world beyond Earth.
Zitat But in a hopeful sign, NASA’s Deep Space Network, which sends commands and receives data from spacecraft across the solar system, was receiving telemetry from SLIM or one of the tiny rovers — or both — an hour after landing.
At the post-landing news conference, JAXA officials confirmed flight controllers were receiving telemetry from both SLIM and LEV-1, which was designed to beam data directly back to Earth. LEV-2 relays data back through SLIM.
“We do consider LEV-1 and LEV-2 to have been successfully separated, and we are making an effort to acquire data at this point in time,” said Kuninaka.
As for SLIM, he said engineers doubt the solar cells, mounted on the upper surface of the spacecraft, were damaged in the landing given other systems were working normally after what he described as a “soft” landing.
“The spacecraft was able to send telemetry to us (after landing), which means that most of the equipment on the spacecraft is functional, working appropriately,” he said. “Ten kilometers was the altitude from which descent was made. So if the descent wasn’t successful, then there would have been a (crash) at a very high speed. Then the spacecraft’s function would have been lost completely.
“But now, it is a still sending data properly to us, which means our original objective of soft landing was successful.”
But he said extensive data analysis will be required to determine the spacecraft’s attitude, or orientation, on the surface, to figure out what happened and to find out how precise the landing actually was.
DUBAI, Jan 20 (Reuters) - Iran has successfully launched its Sorayya satellite into orbit, Iranian state media reported on Saturday, in a move likely to increase Western concerns about Tehran's nuclear ambitions. The satellite, which is being developed by the research arm of the civilian Iranian Space Agency, was put into a 750 km (466 mile) orbit, the highest successfully reached by Iran, the reports said. The 50 kg (110 lb) satellite was launched by the Qaem 100, a three-stage solid-fuel rocket built by the elite military Revolutionary Guards, they said.
The U.S. military says the long-range ballistic technology used to put satellites into orbit could also allow Tehran to launch longer-range weapons, possibly including nuclear warheads. Tehran denies U.S. assertions that such activity is a cover for ballistic missile development and says it has never pursued the development of nuclear weapons. Iran, which has one of the biggest missile programmes in the Middle East, has suffered several failed satellite launches in recent years due to technical issues.
Zitat NASA restores contact with Mars helicopter Ingenuity after communications dropout on latest flight By Monisha Ravisetti - published about 2 hours ago
Everything appears to be fine for our Red Planet robots — NASA can talk to Ingenuity again.
I held my breath for a moment on Jan. 18, when scientists announced they'd lost contact with the Perseverance Mars rover's helicopter friend, Ingenuity.
Ingenuity had been nearing completion of its 72nd flight — a liftoff far past the threshold of "borrowed time" in this case, as the mighty craft was originally built for a mere maximum of five flights. The fate of Ingenuity was pretty uncertain for a short while.
However, I'm pleased to report that Ingenuity has officially regained communication with ground control and continues to surpass the limitations scientists once thought it'd need to live by. According to a Jan. 20 NASA post on X (formerly Twitter), Perseverance had conducted long-duration listening sessions to help pinpoint Ingenuity's signal. "The team is reviewing the new data to better understand the unexpected comms dropout during Flight 72," the post says. ... Everything seemed fine during the probe's 72nd hop on Mars' red surface, as it successfully climbed to an expected maximum altitude of 40 feet (12 meters) and communicated its ascension status with Perseverance, NASA explained. But, during descent, "communications between the helicopter and rover terminated early, prior to touchdown," the agency had said in a statement.
Nonetheless, the glitch is all in the past, so I (and I'm sure many others across the world) can stop holding my breath. Hopefully, we'll be getting some answers as to why the situation arose i
Wie zu sehen, ist der Lander, ganz wie vorgesehen, beim Aufsetzen umgekippt, nur zu heftig & in der falschen Richtung, so daß die Sonnenpaneele nicht Richtung Tagesgestirn, sondern auf den Boden zeigten, als der Lander kopfüber zur Ruhe kam. Das Bild stammt vom kleinen Rover LEV-2, der während des Landevorgangs freigesetzt wurde.
PS. Der Kleine Zyniker™ meint, die knallgelbe Farbe des Landers koppheister in der Mondwüste erinnere ihn nicht nur als Wallace & Gromits erste Exkursion zum Mond, sondern vor allem an die FDP. Die braucht auch stets einen ellenlangen Anflug, und wenn es ans Landen geht, fällt sie verläßlich um - und stets zur falschen Seite.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat The image of the lander, which apears to be tipping on its front, was taken by LEV-2, which was ejected to the moon's surface alongside LEV-1 moments before SLIM's touchdown.
The picture reveals an unexpected scenario: SLIM's front is seen resting on the lunar terrain, its solar panels unfortunately obstructed, cutting off the potential for solar power generation. This unforeseen event left the lander relying on its limited battery reserves, which has already depleted.
Communication between LEV-1 and LEV-2 has been confirmed to be functioning normally, a silver lining amidst the complications. The images captured by LEV-2 and transmitted back to Earth using LEV-1's communication systems offer a clear view of SLIM and its immediate surroundings.
The success of the mission now hinges on whether the lander achieved the targeted 100-meter landing precision—a detail that will require months of analysis to ascertain. The initial descent proceeded without incident until a sudden loss of thrust occurred at approximately 50 meters above the lunar surface. Subsequent images have revealed that one of the main engine's nozzles detached, a critical malfunction that could have spelled disaster for the mission.
However, thanks to the redundancy built into the spacecraft's design, SLIM was able to continue its descent using only one main engine. While this engineering feat allowed the lander to reach the moon's surface, it was unable to counteract lateral movement completely, resulting in the lander's less than optimal orientation upon landing.
Zitat TOKYO, Jan 25 (Reuters) - Japan's moon lander achieved an unusually precise touchdown within 100 m (328 feet) of its target, the space agency said on Thursday, after the nation became the fifth to put a spacecraft on the moon with the weekend touchdown of its SLIM probe.
The Japan Aerospace Exploration Agency (JAXA) said it received all data about the touchdown of its Smart Lander for Investigating Moon (SLIM) within the 2 hours and 37 minutes before the lander lost power.
One of the lander's two main engines probably stopped in the final phase of touchdown, so that it drifted 55 m (180 ft) away from the target site to an unintended position, Sakai said. In the absence of engine trouble, it could have landed as close as 3 m to 4 m (10 ft to 13 ft) from the target, he said. The lander was toppled on the gentle slope of a crater on the moon's surface, in a picture, opens new tab published by JAXA and taken by a wheeled rover SLIM deployed during touchdown.
Zitat Things didn't go entirely to plan that day, however; SLIM's handlers couldn't confirm its status immediately after touchdown and eventually determined that its solar panels weren't generating electricity.
The newly released photo shows why that may be: SLIM came to rest on its head, which was not the desired orientation. So the lander hasn't been able to harvest sunlight as expected.
But the fact that the photo made it down to mission control shows that its bantam daughter craft — LEV-2 and LEV-1 — deployed from SLIM during the descent as planned and operated successfully on the lunar surface.
"This image was transferred to the ground via LEV-1, and it was confirmed that the communication function between LEV-1 and LEV-2 was operating normally," JAXA officials wrote in the same statement.
"Additionally, since LEV-2 was deformed from its spherical state in its stored state, we were also able to confirm that it was successfully deployed and driven on the lunar surface after being released from SLIM," they added. (The tennis-ball-sized LEV-2 was designed to shift from a spherical shape into two halves, then crawl around on the moon.)
On Monday (Jan. 21), JAXA said that SLIM remains alive, though silent, on the lunar surface, and its handlers are preparing for a possible recovery of the lander.
The agency provided another update Wednesday night U.S. West Coast time (Thursday afternoon, Jan. 25, Japan time) during a press conference held in Japanese. The mission team still holds out some hope for a SLIM revival, at least until Feb. 1, when the sun will set at the probe's landing site, according to Dawoon Jung, a lunar mission engineer at the Korea Aerospace Research Institute who live-tweeted Wednesday night's press conference.
Zitat Dawoon Jung@dirkpitt2050 Looks like SLIM nozzle failure is similar to what was thought to have happened to the Akatsuki Venus spacecraft - and no coincidence that SLIM nozzle design builds on Akatsuki heritage!
Zitat Dawoon Jung@dirkpitt2050·28m Replying to @fivemack and @lars_0 Very I nteresting, in fact yes #SLIM uses a similar ceramic silicon nitride thruster as Akatsuki! The Akatsuki one failed probably due to a blocked helium valve (*); SLIM is using blowdown instead but the nozzle fell off again?!
One thing that is unclear is, the #SLIM main engine nozzle that fell during hovering at 50m was said to have fallen off due to an "external" reason. Not sure what "external" means
It doesn't appear that the lander collided with anything since that would have shown in the navigation camera image
外的 is the word used - in Japanese it means "concerning the exterior" or "happened to the exterior" so it's very vague, and quite puzzling since the only forces on an engine nozzle would be from within (engine exhaust) one would think? #SLIM
#SLIM will be in Sun until the end of January. If it recovers it will power on by itself and will transmit after receiving ground commands
Question from press about #SLIM recovery chances under such extreme temperatures: JAXA thinks the chances are not zero and also there is non-zero chance the solar arrays might be physically damaged
Regardless, very impressive @SLIM_JAXA landing even suffering from such a critical anomaly! 11:40 AM · Jan 25, 2024
Zitat Dawoon Jung@dirkpitt2050 Lunar Mission engineer at KARI making Korea's first moonshot happen. Space Exploration Advocate and Software Engineer. #ISUnet #SSP13 #MSS14
Zitat Back from the brink: Akatsuki returns to Venus - by Ralph Lorenz Tuesday, September 8, 2015
This compact spacecraft was developed by JAXA to observe Venus from orbit with a set of innovative cameras to monitor its climate, weather, and surface. Unfortunately, Akatsuki's arrival did not go as planned. Orbit insertion is a tense moment for operators of planetary spacecraft. This crucial operation marks the end of a usually quiet cruise, and the busy transition to operations around the target planet and, hopefully, to routine scientific observations. While usually taken somewhat for granted, it poses mechanical and thermal stresses on vehicle components and makes unforgiving demands on attitude and timing. Usually there is only one chance to get it right.
Like most spacecraft, Akatsuki has an attitude control system using small monopropellant hydrazine thrusters. For major maneuvers, and especially the orbit insertion burn, Akatsuki has a large main engine. For large changes in velocity, the low specific impulse of monopropellant hydrazine would lead to prohibitive fuel loads, and a higher performance system is needed. In many spacecraft this is the hypergolic combination of dinitrogen tetroxide (sometimes abbreviated NTO, or mixed oxides of nitrogen MON) and a hydrazine derivative like monomethyl hydrazine (MMH). The hydrazine derivatives are usually preferred over “straight” hydrazine due to their better chemical stability and lower melting points, which means freezing of the fuel lines is less of a concern. Cassini, for example, with a launch mass of over five tons, has a monopropellant hydrazine attitude control system and a separate bipropellant system for orbit insertion and large maneuvers.
The throat and nozzle of a bipropellant engine sees exceptionally high temperatures, and careful design and often expensive exotic materials are needed (for example, the Leros engines use a niobium alloy nozzle with a disilicide coating.) Correct fuel flow is critical, with engines being run slightly fuel-rich. This creates a film of fuel vapor helping limit the heat load on the walls of the combustion chamber and nozzle throat, a process known as “film cooling.”
The propulsion system schematic shows how fuel (N2H2) and oxidizer (MON3) are forced into the engine by a helium pressurant (GHe). The pressure upstream of both the fuel and oxidant tanks is maintained at a constant level by one of two pressure regulators (RG-1 and -2), and the gas flows through valves (CV-F, CV-O, and GLV) intended to avoid upstream migration of propellant vapors (it was such migration that may have been responsible for the Mars Observer failure.) The gas pressure in the tanks forces the propellant through the lines into the Orbiter Main Engine (OME).
With the fuel pressure declining, the fuel flow into the engine becomes reduced, and the thrust falls, as evidenced by the spacecraft acceleration history, which is falling from its initial value of 0.9 m/s2 (0.09 g) instead of rising. By itself that might not be critical: engine underperformance can sometimes be made up simply by running the engine for longer. But while the fuel flow was falling, the oxidant flow remained constant as it was supposed to, and so the fuel-oxidant mixture in the engine became progressively leaner, allowing combustion temperatures and especially the nozzle throat temperature to increase.
After 152 seconds, this temperature rise led to a sudden change. The thrust drops precipitously (the acceleration dropping to about 0.5 m/s2), but the real key is in the attitude control data. Whereas up to this point, the attitude rates are all low (Figure 7), indicating a steady orientation, at the same instant as the thrust drop, the x-axis angular velocity suddenly starts ramping up. The angular velocity increases at about 5 degrees per second per second (Figure 8): this acceleration requires a strong torque to be whirling the spacecraft around. In fact, the only way to develop this much torque is if much of the engine thrust were pushing not along the x-axis as it had been, but were suddenly emerging partly sideways (Figure 9). The conclusion is clear: part of the nozzle fell off!
Had this been a conventional metal nozzle, it would likely have partly burned through, perhaps seeing some sideways thrust, and would have some thrust drop. Eventually the result might have been the same, but the degradation would probably have been more gradual, whereas the ceramic material cracked suddenly with the thermal stress, giving a very sharp change in the thrust and torque.
As the angular rate climbed to 12 degrees per second, the spacecraft’s on-board fault protection recognized that something was badly wrong, and shut down the engine. Akatsuki sailed past Venus without stopping.
JAXA controllers quickly diagnosed the status of the vehicle, and managed to snap a few pictures of the planet before the spacecraft receded to a distance where Venus shrank to a point, at least demonstrating that several of the cameras worked. The telemetry recording the propulsion system behavior pointed to the culprit. After the engine burn, the fuel-side pressure slowly climbed back to the intended level, implying that some helium was getting through to the tank, just not quickly enough to keep up with fuel usage during the main engine burn. It seems the non-return valve had been (mostly) held shut, perhaps by salts formed by corrosion of the valve seat by fuel vapor. That couldn’t be fixed, now, but perhaps the main engine could be used in short bursts.
Tests on the ground replicated the failure of the engine under low fuel flow conditions, and indeed the nozzle fractured.
"Und ihr könnt sagen, ihr seid dabei gewesen." Goethe, bei der Kanonade von Valmy, zitiert vd FAZ auf S. 1. am 5. Oktober 1957 aus Anlaß des Starts von Sputnik 1.
Zitat von Ulrich Elkmann im Beitrag #58 16:20. 2. Schwebestopp in 50 m Höhe zum Scannen des Geländes. 16:21. "MLM" - Landung. Warten auf Telemetriedaten des Landers.
Zitat von Ulrich Elkmann im Beitrag #67 One thing that is unclear is, the #SLIM main engine nozzle that fell during hovering at 50m was said to have fallen off due to an "external" reason. Not sure what "external" means
At a press conference on Jan. 25, 2024, 05:00 UTC, JAXA officials reported that during descent, SLIM had arrived at an altitude of 50 meters, and had slowed to hover. At around this time, the spacecraft suffered an anomaly which caused terminal damage to one of the two main engines. Before the anomaly, officials say that SLIM was targeting a touchdown within 3 or 4 meters of the target.
Despite the loss of one engine, the craft was still able to descend at about 2 to 3 meters per second. However, the uneven thrust caused a lateral movement of 9 meters per second to the East, which could not be countered by the thrusters. This caused SLIM to tip over into a nose-down attitude about 55 meters from the target but with the vital solar cells pointing West.
Der Kleine Zyniker meint: ich hätte das hier nicht unter dem Motto "umfallende Raketen" einstellen sollen. Auf dem Olymp nimmt man so etwas gerne als Serviervorschlag.
PS.
Zitat Scott Manley@DJSnM After the nozzle failure the on board guidance apparently had a contingency mode to handle the loss of one engine and continued to the landing. Compare this to Chandrayaan-2 and Luna 25 where the software was incapable of adapting to the situation. 4:59 PM · Jan 25, 2024
Sure other nations have landed spacecraft on the moon, but in Japan a toy company designed a successful lunar rover.
Zitat Ingenuity Mars helicopter mission ends after 72 flights
Jeff Foust January 25, 2024
NASA has declared the end of the mission for the Ingenuity Mars helicopter after 72 flights, exceeding even the most optimistic expectations.
NASA announced Jan. 25 that at least one of Ingenuity’s rotor blades sustained damage on its most recent flight Jan. 18. On that flight, contact between the helicopter and the Perseverance Mars rover was interrupted during the helicopter’s descent, but restored the following day.
“It is bittersweet that I must announce that Ingenuity, the little helicopter that could,” NASA Administrator Bill Nelson said in a video message on social media, “has now taken its last flight on Mars.”
The Jan. 18 flight was intended to be a simple up-and-down flight to determine the helicopter’s location after it executed an emergency landing on its previous flight Jan. 6. The helicopter ascended to its planned altitude of 12 meters and hovered for 4.5 seconds before beginning its descent at a speed of one meter per second. Contact was interrupted when Ingenuity was about one meter above the surface.
While Ingenuity is upright and in communication with controllers, images it returned showed damage to the tip of one of its rotor blades. “We’re investigating the possibility that the blade struck the ground,” Nelson said. NASA said in a statement it was still studying what caused the loss of communications and how the helicopter landed.
An image returned by Ingenuity after its 72nd flight included a shadow of one of its rotors, showing damage to the blade sustained on the flight. Credit: NASA/JPL-Caltech
In a call with reporters, Teddy Tzanetos, Ingenuity project manager at NASA’s Jet Propulsion Laboratory, said about 25% of the rotor blade was lost, rendering Ingenuity unflyable. He said given the speed of the rotors — about 2,500 rpm — it is likely other blades were also damaged at landing, something the project team hopes to confirm with additional images. No other major subsystems on the helicopter show signs of damage.
“Whether or not the blade strike occurred, which led to the communications loss, or there was a communications loss and a power brownout which then led to the rotor strike, we will never know,” he said, because of a loss of data during the incident, but added that the project team would try to piece together their best guess of what happened with the data they do get.
One possibility is that the featureless terrain that Ingenuity was flying over may have confused the helicopter’s navigation system. Such systems work by tracking features on the surface and correlating them, throwing out spurious ones. “The danger is when you run out of features, you don’t have very many to navigate on. You’re not able to establish what that consensus is and you end up tracking the wrong kinds of features,” said Håvard Grip, the “pilot emeritus” for Ingenuity, on the call.
In such a scenario, he said, the helicopter may think it’s moving horizontally away from its target landing site and overcorrects. “It’s likely it made an aggressive maneuver to try and correct that upon landing, and that would have accounted for sideways motion and tilted the helicopter,” he said. That could either have caused a blade to strike the ground or to lose power before landing.
Zitat 小型月着陸実証機SLIM@SLIM_JAXA Communication with SLIM was successfully established last night, and operations resumed! Science observations were immediately started with the MBC, and we obtained first light for the 10-band observation. This figure shows the “toy poodle” observed in the multi-band observation. 1:36 AM · Jan 29, 2024
Zitat AMSAT-DL@amsatdl Good morning, there have been no further transmissions from #SLIM @SLIM_JAXA since 22:33 UTC yesterday evening. Assuming that #JAXA will resume when the Moon rises over Japan and it's groundstation. Chiba station has SLIM AOS (0 deg elevation, Moon rise) Jan 29 [Mon] 1120 UTC. At that time the Moon has already set over @SternwarteBO in Germany. 8:49 AM · Jan 29, 2024
AMSAT-DL@amsatdl non-profit, designing, building and operating hamradio #AMSAT satellites since 1973. Home of the Phase3 satellites and first Phase4A geostationary #QO100 Sternwarte Bochum, Germanyamsat-dl.org
Sternwarte Bochum. Erinnert sich noch jemand an "Kap Kaminski"?
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat pi9cam@PI9CAM The team of the Japanese @LEV1_Rover_SLIM Moon rover might have heard a carrier from LEV-1. We will track the Moon tonight 28 Jan. with the 25m Dwingeloo @radiotelescoop to check. We will stream our signal (from 19:30 UTC to about 20:30 UTC) to WebSDR: http://websdr.camras.nl:8901/?tune=437410.00usb 6:23 PM · Jan 28, 2024
Zitat AMSAT-DL@amsatdl Good morning, there have been no further transmissions from #SLIM @SLIM_JAXA since 22:33 UTC yesterday evening.
Zitat AMSAT-DL@amsatdl The Moon has set over Germany now. #SLIM will be visible (AOS) again in 12 hours, when we will continue coverage on our live stream 9:51 AM · Jan 29, 2024
Valerio Arne Saknussem@VSaknussem·1h Does that mean that we have to wait only a few hours from now before SLIM wakes up again? :-)
AMSAT-DL@amsatdl Yes, we can assume that JAXA let #SLIM fully re-charge while not in view of the Japanese Groundstation and turn it on as soon as the Moon rises over Japan to continue scientific mission. Time is running, the Sun sets Jan 31 just after 0900 UTC, thus SLIM gets only 4 more days of sufficient sunlight. 9:07 AM · Jan 29, 2024
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einer Mondmission? Wo habe ich das doch nochmal gehört? #Astrobotic #Peregrine