Zitat von Ulrich Elkmann im Beitrag #22Nächster Schritt der Vorbereitung. Heute Mittag (MESZ) Start des CAPSTONE-Cubesats von Neuseeland
Zitat Rocket Lab @RocketLab
The Moon just got a little closer! We've successfully ignited Photon's HyperCurie engine a 6th time, raising #CAPSTONE's apogee to 69,680 km. Since we combined 2 burns into 1 for this maneuver, only 1 final burn remains to set CAPSTONE on a ballistic lunar transfer to the Moon
12:51 PM · Jul 1, 2022·Twitter Web App
The next and final burn is designed to set CAPSTONE on a ballistic lunar transfer trajectory to the Moon travelling at 24,500 mph (39,400 km/h) to break free of Earth’s orbit. This final maneuver is currently scheduled to take place as early as July 4th.
Zitat Advanced Space @AdvancedSpace This animation shows how the Sun's gravity enables Ballistic Lunar Transfers(BLTs). The BLT will allow the #CAPSTONE spacecraft, which launched on Monday, to reach the Moon with minimal fuel. The BLT path is traced by the blue line. The Earth is at the center. #Innovation2Orbit 1:38 AM · Jul 1, 2022·Hootsuite Inc.
Zitat NASA's Exploration Ground Systems @NASAGroundSys
The team is planning for the first motion of the @NASAArtemis I rollback of @NASA_SLS, @NASA_Orion, and mobile launcher on top of the crawler transporter to the Vehicle Assembly Building for 11:00 pm EDT tonight due to weather.
Zitat The 322-foot-tall (98-meter) moon rocket rolled off its posts at pad 39B at 4:12 a.m. (0812 GMT) Saturday, about five hours behind schedule. A diesel-powered crawler-transporter will carry the Space Launch System rocket down the ramp and along the rock-covered crawlerway on the 4.2-mile (6.8-kilometer) journey back to the Vehicle Assembly Building, a trip expected to take 8 to 12 hours. ... Weber said the ground crew will be “hustling” to roll the rocket back to pad 39B after the flight termination system check. The rocket will need to spend 10 to 14 days on the pad before the first launch attempt, and the schedule currently shows the Artemis 1 team could fit in three launch attempts before the 20-day flight termination system certification clock expires.
NASA officials are expected to set a target launch date as soon as next week.
#CAPSTONE appears to have stopped communicating with #NASA's Deep Space Network (DSN). After the spacecraft was deployed early on July 4th, it communicated successfully with the DSN station in Madrid, Spain.
7:16 AM · Jul 5, 2022·Twitter Web App
Scott Tilley 🇺🇦 @coastal8049 · 9h Replying to @coastal8049 Shortly afterwards a number of reports from amateur observers in Europe independently confirmed RF emissions from #CAPSTONE.
This afternoon, I swung my X-band antenna toward #CAPSTONE and noted no signal, curious I checked DSN NOW. Noticed that DSS 26 in Goldstone was transmitting and DSS 25 was receiving but no downlink was indicated for most of the afternoon while I monitored.
The experience we are witnessing today reminds me of the response after India's Vikram lander crashed on the Moon in 2019, where the DSN sent signals for days hoping to establish contact with the mission.
I hope this is just a transient anomaly for #CAPSTONE and things will return to normal soon. Monitor DSN NOW and look for signals from "CAPS" flowing into the antenna to indicate received signals. The out flowing signal is the call into the ether for Earth...
Zitat AkaSci 📡 @akaschs Why is the @NASA #CAPSTONE spacecraft not communicating with ground control? No word yet from @AdvancedSpace
Any informed guesses? 1. Spacecraft is off-course 2. Solar panel failure 3. Antenna mispoint, attitude loss 4. Comm system failure 5. Temporary glitch (let's hope) 6. ? 1/
The NASA #CAPSTONE spacecraft separated from @RocketLab’s Photon upper stage more than 24 hours. After some initial comm with DSN Madrid, its downlink signal has not been detected. DSN was transmitting all day yesterday, but not at this point. 2/
#CAPSTONE is about 200K km from earth, on its way to insertion into a Near-Rectilinear Halo Orbit (NRHO) around the moon on Nov 13. Let's hope that the comm loss is a temp one. 3/
Looks like Photon's last Hypercurie burn (#7 in diagram) was shortly after separation (around 03:00 ET) and is intended to maneuver the 2nd stage to a lunar flyby and then into interplanetary space (probably a sun orbit). 4/ 3:44 PM · Jul 5, 2022·Twitter Web App
Zur Erinnerung: CAPSTONE soll als erste Raumsonde in die Umlaufbahn um den Mond einschwingen, die für die Gateway-Raumstation vorgesehen ist, die als Basis für die Ausflüge zur Mondoberfläche dienen soll. Der Near-Rectilinear Halo Orbit verläuft so, daß ein Umlauf um den Mond genau 7 Tage dauert & die nächste Annäherung mit 1400 km über dem Mondsüdpol stattfindet. Die weiteste Entfernung beträgt dann 70.000 km. Der "Photon"-Antrieb, der unter 4/ erwähnt wird, ist der Raketenmotor der Sonde, der nach der 6. Zündung gestern abgetrennt worden ist. (Im Diagramm noch mit #7 bezeichnet, weil die 5. & 6. Zündung zusammengelegt worden sind.)
Zitat "DSN Now is currently undergoing maintenance."
Zitat Scott Tilley 🇺🇦 @coastal8049 RE: #CAPSTONE. All is not lost. #NASA knows where the spacecraft is for some time to come thanks to gravity. Engineers have plans to deal with events like this. Lets watch and hope for it to return to speaking to us. 9:17 AM · Jul 5, 2022·Twitter Web App
Following successful deployment and start of spacecraft commissioning on July 4, the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) spacecraft experienced communications issues while in contact with the Deep Space Network. The spacecraft team currently is working to understand the cause and re-establish contact. The team has good trajectory data for the spacecraft based on the first full and second partial ground station pass with the Deep Space Network. If needed, the mission has enough fuel to delay the initial post separation trajectory correction maneuver for several days. Additional updates will be provided as soon as possible.
Update. Mittlerweile ist die Webseite des Deep Space Network wieder oben. Demzufolge sendet Antenne DSS 26 in Goldstone, Arizona zurzeit Signale zur Sonde, empfängt aber nichts.
During commissioning activities an anomaly was experienced related to the communication subsystem; the operations team is actively working this issue with the Deep Space Network and determining the best next steps.
As a result of this anomaly, the first trajectory correction maneuver – originally scheduled for the morning of July 5th – has been delayed. This maneuver is designed to more accurately target the transfer orbit to the Moon. This maneuver is the first in a series that are designed to make small corrections to increase the accuracy of the transfer orbit to the Moon. The spacecraft remains on the overall intended ballistic lunar transfer (BLT) while this targeting maneuver is delayed. One of the benefits of the BLT, the designed trajectory, is its robustness to delays such as this. The mission transfer approach and system margins provide time to resolve and understand this anomaly before proceeding with the first trajectory correction maneuver. At the time of publication, the CAPSTONE spacecraft is currently approximately 285,000 km from Earth (~8 times GEO) on its planned ballistic transfer orbit to the Moon.
Zitat Phew! NASA's CAPSTONE moon probe phones home again
By Mike Wall published 24 minutes ago
The CAPSTONE team has re-established contact with the 55-pound (25 kilograms) cubesat.
NASA's tiny CAPSTONE moon probe is back in touch with its handlers, ending a short but spooky silent period.
The 55-pound (25 kilograms) CAPSTONE went dark on Monday (July 4), shortly after separating from its Rocket Lab Photon spacecraft bus and heading toward the moon. The mission team immediately set to troubleshooting, and their efforts have already been rewarded.
"We have re-established communications with CAPSTONE. The spacecraft is looking happy and healthy. More details to come," Colorado-based company Advanced Space, which operates the mission for NASA, said via Twitter today (opens in new tab) (July 6).
CAPSTONE made contact with the mission team two times via NASA's Deep Space Network shortly after separation, but it then went dark, for reasons that remain mysterious.
The loss of contact forced the CAPSTONE team to delay the cubesat's first trajectory-correction engine burn, which had been scheduled for yesterday. But that shouldn't be a big deal; the spacecraft has enough fuel to handle a delay of "several days" in this initial burn, NASA officials said in another update yesterday (opens in new tab).
Zitat SpaceX rolls Starship prototype to launch pad ahead of orbital test flight (photos)
By Mike Wall published 21 minutes ago
Ship 24 just made a big move.
We may not have to wait too much longer for the first-ever orbital test flight of SpaceX's Starship deep-space transportation system.
SpaceX is developing Starship to carry people and cargo to Mars, the moon and other far-flung destinations. The system consists of two elements, both of which are designed to be fully and rapidly reusable: a huge first-stage booster called Super Heavy and a 165-foot-tall (50 meters) upper-stage spacecraft called Starship.
Starship prototypes have conducted a handful of high-altitude test flights to date, but the vehicle has yet to go orbital. SpaceX plans to change that soon; the company is gearing up to launch an orbital test mission with the system, which will also mark the spaceflight debut of Super Heavy.
And those preparations are ramping up. Ship 24, the Starship vehicle that will fly the orbital mission, just rolled out to the launch pad at Starbase, SpaceX's South Texas facility, company representatives announced via Twitter today (July 6). In that same post, SpaceX shared three photos of the big spacecraft on the move.
Ship 24 will launch atop a Super Heavy known as Booster 7. That rocket is already at the pad and may conduct a static fire test — a prelaunch trial in which a rocket's engines are lit while the vehicle stays anchored to the ground — in the coming days.
Zitat von July 6, 2022 5:36 pmFollowing Communications Recovery, NASA’s CAPSTONE Prepares for First Maneuver
Following communications issues, mission teams for NASA’s Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) have re-established contact with the spacecraft through NASA’s Deep Space Network. Data received from CAPSTONE shows that the spacecraft is in good health and operated safely on its own while it was out of contact with Earth. Teams are preparing to carry out CAPSTONE’s first trajectory correction maneuver – which will more precisely target CAPSTONE’s transfer orbit to the Moon – as early as 11:30 a.m. EDT on July 7. As originally planned, CAPSTONE will arrive to its lunar orbit on Nov. 13.
The CAPSTONE team is still actively working to fully establish the root cause of the issue. Ground-based testing suggests the issue was triggered during commissioning activities of the communications system. The team will continue to evaluate the data leading up to the communications issue and monitor CAPSTONE’s status.
The mission team, led by Advanced Space, initially re-established contact with CAPSTONE at 9:26 a.m. EDT on July 6. The signal confirmed that CAPSTONE was in the expected location, as predicted based on data from CAPSTONE’s initial contacts on July 4. The team started recovery procedures and began receiving telemetry data from the spacecraft at 10:18 a.m. EDT.
Zitat Eric Berger @SciGuySpace It is now more than theoretical that SpaceX's Starship and NASA's Space Launch System rocket could make their orbital launch attempts during the same month (August 2022). 7:56 PM · Jul 6, 2022·TweetDeck
The off the record, for planning purposes only dates for the two launches are now within 21 days of one another. The Starship launch date is much more slippery, but if they get through the static fire test in the next week or two, oh my.
Zitat Fifty-three more Starlink internet satellites are fastened to the top of a SpaceX Falcon 9 rocket for liftoff Thursday from Cape Canaveral, the first of five Falcon 9 flights scheduled for July.
SpaceX has two launch opportunities available Thursday at 9:11 a.m. EDT (1311 GMT) and 10:30 a.m. EDT (1430 GMT). A 229-foot-tall (70-meter) Falcon 9 rocket will take off from pad 40 at Cape Canaveral Space Force Station and head northeast to place the 53 Starlink satellites into orbit.
The launch Thursday is designated Starlink 4-21, and marks the 49th SpaceX mission primarily dedicated to launching satellites for the Starlink broadband network. SpaceX said in May it has more than 400,000 subscribers for the Starlink internet service, which is designed to eventually provide high-speed, low-latency connectivity anywhere in the world.
SpaceX is about halfway through the build-out of its first-generation network, which will number around 4,400 active satellites, according the company’s filings with the Federal Communications Commission. With the 53 satellites set for launch Thursday, SpaceX will have shot 2,759 Starlink spacecraft into orbit, including prototypes and decommissioned satellites no longer in service.
A tabulation by Jonathan McDowell, a respected expert tracker of spaceflight activity, showed SpaceX has more than 2,400 Starlink satellites currently operating in orbit. Around 2,030 satellites are providing commercial services, according to McDowell. That’s nearly five times more than any other satellite fleet.
The launch Thursday — the 28th SpaceX mission this year — is the first of five Falcon 9 missions scheduled for July. They include three more Starlink missions later this month, plus the launch of a Dragon cargo ship to the International Space Station on July 14.
This CAPSTONE update is really interesting. There were two problems here: an improperly formatted command sent up, and a flight software flaw. And still, the small spacecraft survived. Hard not to root for the little guy.
Zitat AkaSci 📡 @akaschs Mission team determines cause of comm issue for NASA #CAPSTONE. Root cause = Human error + software weakness; But eventual recovery by flight software(). Also confirms traj corr maneuver at 11:30 a.m. ET @nascom1 @planet4589 @cathirame @AdvancedSpace
Zitat After a thorough review, teams have determined what led to CAPSTONE’s communications issue that began on July 4.
During commissioning of NASA’s CAPSTONE (short for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment) spacecraft, the Deep Space Network team noted inconsistent ranging data. While investigating this, the spacecraft operations team attempted to access diagnostic data on the spacecraft’s radio and sent an improperly formatted command that made the radio inoperable. The spacecraft fault detection system should have immediately rebooted the radio but did not because of a fault in the spacecraft flight software.
CAPSTONE’s autonomous flight software system eventually cleared the fault and brought the spacecraft back into communication with the ground, allowing the team to implement recovery procedures and begin commanding the spacecraft again.
While CAPSTONE was out of contact with Earth, the spacecraft autonomously maintained its orientation to keep its antenna pointed towards Earth and allow the solar panels to keep its battery charged. CAPSTONE also used its thrusters to perform a standard maneuver to dump excess momentum from its reaction wheels, which are internal wheels that help the spacecraft rotate and point itself.
Zitat NASA’s CAPSTONE spacecraft, a miniature pathfinder for future lunar crew missions, has overcome a communications outage and performed its first course correction maneuver since a Rocket Lab propulsion module gave the probe a final push toward the moon July 4.
The $30 million mission launched June 28 from New Zealand on a Rocket Lab Electron booster, a light launcher typically used to carry small satellites into low Earth orbit. With some adjustments, like saving weight by removing on-board cameras, the two-stage Electron launcher hauled into a low-altitude orbit a Rocket Lab-developed space tug called Lunar Photon and NASA’s CAPSTONE spacecraft, with a combined eight of about 660 pounds (300 kilograms).
The Lunar Photon, with solar panels, rechargeable batteries, and a small 3D-printed rocket engine of its own, propelled the 55-pound (25-kilogram) CAPSTONE spacecraft into ever-higher orbits with a sequence of seven burns over six days, finally nudging the small satellite on a trajectory to carry it more than three time farther than the moon.
The mission will scout a halo-like, elongated orbit around the moon that NASA has chosen for a future mini-space station called the Gateway. The Gateway station, part of NASA’s Artemis lunar program, will serve as an experiment platform and a stopover for astronauts traveling between Earth and the surface of the moon.
No other spacecraft has flown in the unique path around the moon, called a near rectilinear halo orbit, or NRHO. The halo orbit will take CAPSTONE — and eventually the Gateway station — as close as 1,000 miles (1,500 kilometers) from the moon’s North Pole and as far as 43,500 miles (70,000 kilometers) from the South Pole. Each orbit of the moon will last about six-and-a-half days, according to NASA.
Zitat von Ulrich Elkmann im Beitrag #39 The Gateway station, part of NASA’s Artemis lunar program, will serve as an experiment platform and a stopover for astronauts traveling between Earth and the surface of the moon.
Zitat Jeff Foust@jeff_foust One tidbit from a Coalition for Deep Space Exploration webinar about the lunar Gateway today: NASA hopes to have a new agreement with an unnamed partner in place by the end of the year or early next year to provide the airlock (originally projected to come from Russia.) 8:48 PM · Jul 29, 2022·Tweetbot for Mac
Zitat Sold-out hotels. Excitement that seems to grow by the day. The potential for hundreds of thousands of visitors, support staff, and more.
These are just a few of the factors being calculated into preparations for Artemis I, the first launch of NASA's moon-focused Space Launch System rocket slated for Aug. 29. Standing 322 feet tall, it promises to be the biggest, most powerful rocket to launch from the Space Coast in years – bringing with it a level of excitement to match.
All told, Space Coast officials are expecting at least 100,000 visitors for the rocket's first window, which includes opportunities on Aug. 29, Sept. 2, and Sept. 5 (Labor Day). Currently, T-0 on Aug. 29 is set for 8:33 a.m. ET. Pad 39B will host.
Zitat The Space Coast isn't a stranger to launch day crowds. During the space shuttle era that ran through 2011, half a million or more visitors would sometimes flood the area, scooping up hotel rooms and packing local businesses.
Since then, crowds have been more smaller, but still significant. Even during the height of the coronavirus pandemic, thousands still flocked to Brevard County to see launches.
Some of the recent SpaceX Crew Dragon launches, which take astronauts to the International Space Station from KSC, have drawn between 100,000 and 250,000 visitors, according to Peter Cranis, executive director of the Space Coast Office of Tourism. It wouldn't be a stretch to expect more than 100,000 for Artemis I.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat Andrew @Cosmic_Andrew1 -LH2 leak has been fixed -Batteries have been installed -FTS decoder installed and booster auto destruct units have been tested -Work continues on ICPS TPS blanket installation -Replacing seal between the mobile launcher’s crew access arm and Orion’s launch abort system 9:30 PM · Aug 1, 2022·Twitter Web App
Zitat Engineers successfully reconnected the hydrogen tail service mast umbilical where a hydrogen leak was detected during the last wet dress rehearsal test. Teams tested the connection and did not detect any leaks under ambient conditions in the Vehicle Assembly Building. Up next, technicians will perform additional work to return the section to its launch configuration.
Technicians finished installing the rocket’s flight batteries. As part of operations to prepare the flight termination system, engineers installed and tested the core stage flight command receiver decoders and also tested the solid rocket boosters’ automatic destruct units. Work continues to complete installation of the thermal protection system blankets on the interim cryogenic propulsion stage and launch vehicle stage adapter. Following completion of the upper stage closeout work, teams will conduct flight closeout inspections, which includes removing access platforms and installing flight doors replacing the ground support equipment coverings on the core stage.
Teams also are replacing the inflatable seal between the mobile launcher’s crew access arm and Orion’s launch abort system after it experienced some minor damage due to inclement weather sustained while it was out at launch pad 39B for the wet dress rehearsal tests. The seal prevents anything from the outside environment from getting inside the capsule. Once the seal is replaced and tested, engineers will finish installing remaining payloads inside the crew module before SLS and Orion roll back out to the pad for launch.
Das hier war mir bislang durch die Lappen gegangen.
Zu den "sekundären Nutzlasten" der Artemis-I-Mission gehören auch 13 Cube-Sats, die während der Mission ausgesetzt werden sollen. Unter anderem dieser hier:
Zitat Andrew @Cosmic_Andrew1 Launching on Artemis-1 the NEA scout 6u cube sat will unfurl a 925 square feet solar sail(I have no idea how that is possible) to go study the smallest asteroid ever studied. Its propulsion is solar radiation 3:25 PM · Mar 29, 2022·Twitter Web App
The NASA Near Earth Asteroid (NEA) Scout mission will demonstrate the capability of an extremely small spacecraft, propelled by a solar sail, to perform reconnaissance of an asteroid at low cost. The goal is to develop a capability that would close knowledge gaps at a near-Earth asteroid in the 1–100 m range.
Der Satellit hat die Maße 10x20x30 cm und eine Masse von 14 kg. Das Sonnensegel besteht aus eine aluminium-bedampften Kunststofffolie mit einer Dicke von 2,5 Mikrometern (μm) und einer Fläche von 85 m². Als Ziel ist der Asteroid 2020 GE vorgesehen, der im September 2023 die Erde in einer Entfernung von 5,3 Millionen km passieren wird. Der Asteroid hat einen Durchmesser von höchstens 18 m und ist damit das kleinste Ziel, das bislang von einem Raumfahrzeug angeflogen wurde. Interessant deshalb, weil man über die innere Struktur solcher Objekte kaum etwas weiß. Größere Asteroiden oder Kometen sind "fliegende Sandhaufen," die nur ganz locker durch ihre minimale Schwerkraft zusammengehalten werden.
Zitat Date Distance from Earth (km) Velocity (km/s) April 13, 2019 13,024,674 4.266 April 10, 2020 2,080,067 2.154 March 27, 2021 4,866,157 1.546 Feb. 5, 2022 9,875,691 1.769 July 8, 2022 9,303,543 1.619 Dec. 20, 2022 10,857,355 1.688 Sept. 8, 2023 5,724,359 1.447
2020 GE is a very small asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 2020 GE as a "Near Earth Asteroid" due to its orbit's proximity to Earth, but it is not considered potentially hazardous because computer simulations have not indicated any imminent likelihood of future collision.
2020 GE orbits the sun every 368 days (1.01 years), coming as close as 0.97 AU and reaching as far as 1.05 AU from the sun. Based on its brightness and the way it reflects light, 2020 GE is probably between 0.004 to 0.018 kilometers in diameter, making it a small to average asteroid, very roughly comparable in size to a school bus or smaller.
Es handelt sich um die allererste Anwendung eines Sonnensegels bei einer Raumfahrtmission. Und ich habe auch keine Ahnung, wie das sauber auseinandergezogen werden soll. (Es sind zu diesem Zweck 4 schmale Ausleger von jeweils 6,80 m Länge vorhanden, die teleskopartig ausgefahren werden können).
Guckt ihr zum Thema hier:
Zitat …daß jetzt nach dem Verlassen der Atmosphäre Segel aus metallischer Folie mit einer Fläche von einem Quadratkilometer oder mehr entfaltet werden, um den Strahlungsdruck der Sonne aufzufangen. Diese Flüge benutzen im Grunde dieselben Prinzipien, die schon die alten Segelschiffe antrieben“ - hier dürfte es sich um die erste Erwähnung eines Raumschiffantriebs durch Sonnensegel handeln – zumindest im Westen. Die erste explizite Formulierung, den Lichtdruck der Sonne zur Beschleunigung von Raumfahrzeugen zu nutzen, stammt von dem in Lettland geborenen Ingenieur und Raketenpionier Friedrich Zander (russisch: Фридрих Артурович Цандер, 1887-1931), der sich seit 1908 mit Problemen der Raumfahrt befaßte und zusammen mit dem bekannteren Vordenker Konstantin Ziolkowski (1857-1935) im Mai 1924 in Moskau die erste „Raumfahrtgesellschaft,“ Общество изучения межпланетных сообщений (Gesellschaft zum Studium interplanetarer Reisen) gründete. Im gleichen Jahr erschien in der Nummer 13 der Zeitschrift Техника и жизнь (Technik und Leben) eine knappe, stichwortartige Zusammenfassung eines Vortrags, den Zander drei Jahre zuvor bei ersten Treffen zu diesem Thema gehalten hatte: „Перелёты на другие планеты“ (Flüge zu anderen Planeten). Und dort heißt es unter den Punkten 7 bis 10: ... Zumeist wird Ziolkowski in der Literatur als Miturheber der Idee des „Sonnensegels“ (russ: Солнечный парус) „in den zwanziger Jahren“ („1920-е годы“) genannt. Allerdings ist die einzige direkte Erwähnung zum Thema in seiner kurzen, lobenden Antwort auf Zanders Aufsatz erhalten, der zwei Nummern darauf in „Technik und Leben“ erschien. Ich habe nun nicht sämtliche der gut 200 Aufsätze, Arbeiten, und Zuschriften durchgesehen, die Ziolkowskis Oeuvre umfaßt (eine Liste mit Links zu den Texten findet sich hier), aber eine entsprechende Stichwortsuche ergibt keine weiteren Treffer, und ich vermute, daß der Irrtum auf das anonyme Vorwort zu der Auswahlausgabe von 1952 zurückgeht, von wo er sich ungeprüft bis heute in russischen und westlichen Abhandlungen zum Thema fortpflanzt.
Daß Zanders Text die Grundlage für Haldanes Idee gewesen sein dürfte, legt die Erwähnung „Auch die leeren Hecksegmente wurden bei Bedarf nach hinten abgestoßen“ („The empty sections of the tail were also blown backward as required“) nahe, was Zanders Idee, das Material seiner Sonnensegel bei Bedarf als Treibstoff zu verwenden, ja durchaus entspricht. Im Westen waren die Arbeiten Zanders zur Raketentechnik bis zum Erscheinen der ersten russischen Buchausgabe 1967 weitgehend unbekannt (oder in Vergessenheit geraten), aber es ist durchaus möglich, daß eine Übersetzung – oder ein Bericht über die Tagung von 1921 in einer der englischen Zeitungen mit Sympathien für die „rote Revolution“ publiziert worden ist – wie etwa im „Daily Worker,“ für den Haldane seine Kolumne schrieb.
Zitat Four flexible, 6.8 m long booms are responsible for deploying the sail from the initial stowed position in the central 2U of the spacecraft bus. Both the sail and the deployment mechanism are designed by MSFC and based on the technology developed for NASA’s NANO Sail-D and the Planetary Society’s Lightsail-A. 4 Additional propulsion for detumbling and course correction capabilities is delivered by a cold gas thruster system capable of 38 m/s of total ∆V. ... NEA Scout will be ejected from the upper stage of the SLS. The cold gas thrusters will then expend 10 m/s of ∆V to detumble the rapidly spinning spacecraft and target a planned lunar flyby. It will then spend roughly two weeks in the vicinity of the Moon awaiting for the precise opportunity to depart towards the target asteroid. The intervening time will be used to deploy the sail and calibrate communications equipment. At the conclusion of this phase, the cold gas thrusters will perform another small propulsive maneuver, placing the spacecraft on a trajectory towards its primary target. Thereafter, the spacecraft will be propelled primarily by solar sail, with 28 m/s of ∆V being held in reserve for any desirable corrective maneuvers. Upon arrival in the vicinity of the target, NEA Scout will perform a flyby at a velocity of less than 100 m/s relative to the asteroid from a distance of less than 2 km, and use its on-board camera to characterize the asteroid’s shape, spectral type, and rotational properties. However, there is a considerable interest in how the failure of the initial outbound trim maneuver and the subsequent lunar flyby will affect the mission’s success.
Accurate modeling of the effects of solar radiation pressure (SRP) on NEA Scout’s sail is critical to the construction of feasible trajectories. Without resorting to finite element analysis, an optical reflection model offers an excellent approximation of the solar sail’s thrusting capability. The derivation of the model begins with that of a perfectly flat and reflecting surface of arbitrary shape at a distance of 1 AU from the Sun. In this form, all incident photons originating from the Sun are assumed to undergo perfectly elastic collisions with the sail’s surface. Under these assumptions, the acceleration of the sail can be stated in Equation 2.
~asail−1AU =2P0∗Asail msail cos2αˆn(2)
Where P0is the SRP at a distance of 1 AU, Asail and msail are the area and mass of the sail-craft, ˆnis the orientation of the sail in the inertial frame, αis the angle between the sail normal vector and Sun-sail line, and coefficient 2 arises from the perfect reflection assumption. Direction vector ˆnitself is a function of cone angle α, clock angle γ, and the position of the sail craft relative to the Sun. A new term βideal can now be introduced in Equation 3 as the ratio of the local acceleration due to the SRP, and the solar gravity at 1 AU.
βideal =2P0Asail |AU |2 msail µsun (3)
βideal, known as the lightness parameter, is the main performance metric of the sail and is constant with distance from the Sun, owing to the fact that both the SRP and the solar gravity are inverse square fields.8, 9 SRP acceleration at an arbitrary position can now be stated below. As in Equation 1, the Sun’s position ~rs is determined using the DE 431 ephemeris. ¨~rsail =12βideal µsun |~rsc |2(2 cos2αˆn) (4)
For NEA Scout, with a mass and sail area of 12 kg and 86 m2, respectively, the ideal lightness parameter is 0.011. This model can then be modified to account for a non-ideal flat square sail in Equation 5 by considering the optical properties of the sail’s material.3, 10 ¨~rsail =12βidealµsun|~rsc |2(1 + ers) cos2(α) + Bf(1 −s)ercos (α)−(1−er)efBf−ebBbef+ebcos (α)ˆn(5)+(1 −ers) cos αsin αˆt
Terms er and s are the reflectivity and specular coefficients. Bf,Bbare the front and backside Lambertian coefficents of the sail, while ef,ebare the front and backside emissivity coefficients. These are based on updated testing done for the NEA Scout project in 2015 and are available in Table 1.3
The assumption of non-elastic photon collision also introduces a tangential component of SRP acceleration directed in the ˆtdirection that is not present in the ideal formulation. Its propulsive effects are small compared to that of the normal acceleration, but cannot be ignored if one is considering the effects of SRP torque upon the spacecraft. Such analysis is beyond the scope of this paper, but the propulsive effects are included and the sail is operated in an αenvelope that will mitigate negative impact. The αand γangles are not explicitly controlled via modeling of NEA Scout’s attitude control systems. They are, instead, directly chosen in order to produce the desired orientation.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat NASA's Exploration Ground Systems @NASAGroundSys
Vehicle Assembly Building High Bay 3 Platform E was retracted last night. ½ of the platforms are now retracted. Platform K will be retracted tonight, with B, C, E next week, starting on Tues. Join us today at 11:30 ET for an Artemis I mission briefing at http://nasa.gov/live
Zitat Emre Kelly @EmreKelly Good news for Artemis I: the Space Force's Eastern Range calendar has dropped "pending" from the Aug. 29 launch date, so it's now solidly on the schedule for 0833 EDT that day. 8:06 PM · Aug 10, 2022·Twitter Web App
Zitat NASA's Exploration Ground Systems @NASAGroundSys Artemis I Update: Platform D in High Bay 3 of the Vehicle Assembly Building was retracted leaving only platform F remaining, which crews continue to use for access to the vehicle. 11:51 PM · Aug 10, 2022·Twitter Web App
Daß ich es nicht vergesse. Um 23.40 MESZ ist der Start der nächsten Starlink-Tranche von Vandenberg AFB aus erfolgt. Landung der Startstufe um 23:50 auf der Of Course I Still Love You; 10. Flug des Boosters. 46 Satelliten diesmal, weil sie in einem sonnensynchronen Orbit mit 97,6° gegen den Äquator in 560 km Höhe befördert werden. 170. Start für SpaxeX insgesamt.
Zitat 08/13/2022 00:36
The Starlink satellites are expected to release from the front end of the rocket all at once, instead of one-at-a-time or in pairs, as spacecraft often do when separating from a launch vehicle.
The Falcon 9 upper stage will fire thrusters to put itself in a spin before deploying the satellites. Then the rocket will release retention rods that hold the satellites in place on top of the vehicle.
The momentum from the rotation helps the satellites disperse, before the craft individually activated their propulsion systems to begin climbing toward their final operating altitude roughly 348 miles (560 kilometers) above Earth.
SpaceX says injecting the satellites into a lower orbit will allow time for checkouts before orbit-raising using their krypton ion thrusters.
Separation of the Starlink satellites is scheduled for 3:43 p.m. PDT (6:43 p.m. EDT; 2243 GMT).
SpaceX confirms deployment of 46 new Starlink internet satellites, completing the 55th dedicated launch for the privately-funded broadband network. SpaceX has now launched 3,055 Starlink satellites, including spacecraft already retired from service.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat NASA's Exploration Ground Systems @NASAGroundSys
Teams have completed the final flight termination system (FTS) test for Artemis I with @NASA_SLS and @NASA_Orion in the Vehicle Assembly Building at @NASAKennedy.
Engineers and technicians at @NASAKennedy have completed the final testing and checkouts for #Artemis I and are targeting the evening of Tuesday, Aug. 16 for rollout ahead of a targeted Aug. 29 launch.
Zitat von August 15, 2022 9:45 amArtemis I Moon Rocket Ready to Roll to the Launch Pad
Engineers and technicians at NASA’s Kennedy Space Center in Florida have completed the final testing and checkouts of the Artemis I Moon rocket ahead of rolling to Launch Pad 39B. NASA is targeting as soon as 9 p.m. EDT of Tuesday, Aug. 16 for rollout ahead of a targeted Aug. 29 launch.
The crawler-transporter will roll inside the Vehicle Assembly Building (VAB) and under the Space Launch System rocket and Orion spacecraft later today. Teams are currently working to prepare the integrated stack for rollout.
Over the weekend the team completed testing of the flight termination system, which marked the final major activity prior to closing out the rocket and retracting the final access platforms in the VAB.
The agency will provide a live stream of the rollout beginning at 3 p.m. EDT Tuesday, Aug. 16 on the NASA Kennedy You Tube channel.
Zitat NASA's massive moon rocket will roll out earlier than planned
By Meghan Bartels, published about 3 hours ago
It's rare that a spaceflight milestone occurs earlier than planned.
NASA will roll out its massive rocket for a flight around the moon earlier than planned.
The agency had been targeting Thursday (Aug. 18) for the Artemis 1 Space Launch System (SLS) rocket to make the slow trek out to Kennedy Space Center's Launch Complex 39B in advance of blasting off on Aug. 29. But on Monday (Aug. 15), NASA announced that the plan changed, with rollout moved up to Tuesday evening (Aug. 16). You can watch coverage of rollout beginning at 3 p.m. EDT (1900 GMT) courtesy of NASA.
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