Zitat Andrew Jones @AJ_FI Mission extended: the Chang'e-5 orbiter is heading to Sun-Earth Lagrange point 1, according to the link here, citing Hu Hao, a chief designer of Chinese Lunar Exploration Program. Images: Weibo/China航天，NASA。 5:30 nachm. · 20. Dez. 2020·Twitter for Android
Zitat von Spacenews.com, 21 DecChina’s Chang’e-5 orbiter is heading for a gravitationally stable point in space on an extended mission after delivering fresh lunar samples to Earth.
The spacecraft is now heading to a Sun-Earth Lagrange point to carry out observations of the local environment, the Sun, and perform operational tests.
The Chang’e-5 orbiter left lunar orbit late Dec. 12 Eastern along with a return capsule containing lunar samples. The two spacecraft separated around 5,000 kilometers from Earth Dec 16., with the return capsule performing a ‘skip’ reentry into the atmosphere. The return capsule landed at 12:59 Eastern Dec. 16 with 1.731 kilograms of lunar materials.
Meanwhile the orbiter had conducted an avoidance burn. It was initially unclear if the avoidance burn referred to avoiding the return capsule or the Earth’s atmosphere.
Hu Hao, a chief designer of the third (sample return) phase of the Chinese lunar exploration program, told China Central Television Dec. 20 that the orbiter is now on an extended mission to a Sun-Earth Lagrange point.
Hu said the extended mission was made possible by the accurate orbital injection by the Long March 5 launch vehicle, the same rocket which failed in July 2017 and delayed Chang’e-5 by three years. The Chang’e-5 orbiter has more than 200 kilograms of propellant remaining for further maneuvers.
While unspecified, it is believed that the Chang’e-5 orbiter will enter orbit around L1, based on the reference to planned solar observations. The orbiter is equipped with optical imagers.
Chang’e-2, which orbited and mapped the moon in 2010, later visited Earth–Sun L2 Lagrangian point to test tracking and ground networks. It then performed a flyby of asteroid 4179 Toutatis. ... Possible future scenarios for the Chang’e-5 orbiter could include visiting the Sun-Earth L4 or L5 points. These triangular libration points are more stable than the other three points and could harbor near-Earth objects. Imagers could be used to survey the region for speculated Earth Trojan asteroid objects.
Zitat von NASA.gov, 9 Febr 2021NASA Awards Contracts to Launch Initial Elements for Lunar Outpost
NASA has selected Space Exploration Technologies (SpaceX) of Hawthorne, California, to provide launch services for the agency Power and Propulsion (PPE) and Habitation and Logistics Outpost (HAO), the foundational elements of the Gateway. As the first long-term orbiting outpost around the Moon, the Gateway is critical to supporting sustainable astronaut missions under the Agency's Artemis program.
After integration on Earth, the PPE and HALO are targeted to launch together no earlier than May 2024 on a Falcon Heavy rocket from Launch Complex 39A at NASA's Kennedy Space Center in Florida. The total cost to NASA is approximately $ 331.8 million, including the launch servcies and other mission-related costs.
The PPE is a 60-kilowatt class solar electric propulsion spacecraft that will also provide power, high-speed communications, attitude control and the capability to move the Gateway to orbits, providing more access to the Moon's surface than ever before.
The HALO is the pressurized living quarters where astronauts who visit the Gateway, often on their way to the Moon, will work. It will provide command and control serve as the docking hub for the outpost. HALO will support science investigations, distribute power, provide communications for visiting vehicles and lunar surface expeditions, and supplement the life support systems aboard Orion,, NASA's spacrecraft that will deliver astronauts to the Gateway.
About one sixth the size of the International Space Station, the Gateway will function as a way station, located tens of thousands of miles at its farthest distance from the lunar surface, in a near-rectilinear halo orbit. It will serve as a rendezvous point for Artemis astronauts traveling to lunar orbit aboard Orion prior to low-lunar orbit and and the surface of the Mooon. From this vantage, NASA and its international and commercial partners will conduct unprecedented deep space science and technlogy investigations.
Ich nehme an, das Preisschild über $331m bezieht sich auf Start plus Positionierung. Daß die NASA eine komplette Raumstation für einen solchen Schnäppchenpreis erstellen könnte, halte ich für ausgeschlossen. PS. Vielleicht liegt hier auch ein kleiner Buchungstrick vor. Der Kongress hat Ende 2018 für das FY (Fiscal Year) 2019-20 für die Vorplanungen und erste Kontraktvergaben die Summe von 331 Mio. USD freigegeben. In Sachen des "beinahe rechtwinkligen Halo-Orbits" dies hier:
Zitat The Gateway is planned to be deployed in a highly elliptical seven-day near-rectilinear halo orbit (NRHO) around the Moon, which would bring the station within 3,000 km (1,900 mi) of the lunar north pole at closest approach and as far away as 70,000 km (43,000 mi) over the lunar south pole. Traveling to and from cislunar space (lunar orbit) is intended to develop the knowledge and experience necessary to venture beyond the Moon and into deep space. The proposed NRHO would allow lunar expeditions from the Gateway to reach a low polar orbit with a delta-v of 730 m/s and a half a day of transit time. Orbital station-keeping would require less than 10 m/s of delta-v per year, and the orbital inclination could be shifted with a relatively small delta-v expenditure, allowing access to most of the lunar surface. Spacecraft launched from Earth would perform a powered flyby of the Moon (delta-v ≈ 180 m/s) followed by a ≈240 m/s delta-v NRHO insertion burn to dock with the Gateway as it approaches the apoapsis* point of its orbit. The total travel time would be 5 days; the return to Earth would be similar in terms of trip duration and delta-v requirement if the spacecraft spends 11 days at the Gateway. The crewed mission duration of 21 days and ≈840 m/s delta-v are limited by the capabilities of the Orion life support and propulsion systems.
One of the advantages of an NRHO is the minimal amount of communications blackout with the Earth.
Zitat von Ulrich Elkmann im Beitrag #79 Morgen Mittag (bzw. heute Mittag) soll die chinesische Tianwen-1-Sonde folgen. Meldungen über den Status der Mission werden um ca. 14:00 erwartet.
Zitat von Space News.comChina’s Tianwen-1 enters orbit around Mars by Andrew Jones — February 10, 2021
HELSINKI — China’s first interplanetary mission, Tianwen-1, successfully entered Mars orbit Feb. 10 following a 202-day journey through deep space.
Tianwen-1 initiated a near 15-minute burn of its 3000N main engine at 6:52 a.m. Eastern allowing the five-ton spacecraft to slow down and be gravitationally captured by Mars.
The Mars orbit insertion maneuver was designed to place the Tianwen-1 into an elliptical orbit of 400 by 180,000 kilometers inclined by 10 degrees, with an orbital period of 10 days.
With Mars more than 192 million kilometers away from Earth and a light time delay of 10 minutes and 40 seconds, the braking burn was by necessity pre-programmed. Intervention would not be possible in the event of an issue.
Tianwen-1 will gradually lower its orbit to allow for observations of Mars. It will also begin preparations for the entry, descent and landing attempt of a 240-kilogram solar powered rover, an event expected to take place around May or June, according to the China Aerospace Science and Technology Corp.
The orbiter is expected to approach as close as 265 kilometers to the surface, allowing a high-resolution camera to return images with a resolution of better than 0.50 meters per pixel.
This capability will be used to map a targeted rover landing site in Utopia Planitia. Landing coordinates of 110.318 degrees east longitude and 24.748 degrees north latitude had previously appeared in an official Chinese space publication before being removed.
Tianwen-1 joins the United Arab Emirates’ Hope mission, which arrived Tuesday, in orbit around the Red Planet. NASA’s Perseverance rover will arrive and make a soft landing attempt Feb. 18.
Laut Mitteilung von CASC (China Aerospace Science and Technology/中国航天), dem größten Hersteller von Satellitentechnik in China, vom frühen Nachmittag ist die Landung des Rovers für Mai oder Juni geplant.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat For landing astronauts on the moon, Nelson said the goal remains 2024, a deadline set by the Trump administration. But he said he needs more time to review the matter, especially with challenges to the contract for the astronauts' lunar lander.
“That is the intended schedule, but I think we have to put a dose of sobering reality into our analysis," he said from NASA headquarters in Washington.
The lunar expeditions will benefit the Martian crews, according to Nelson. Whether the 2030s is still feasible for human Mars missions, “all of that is being discussed,” he said.
NASA and Northrop Grumman of Dulles, Virginia, have finalized a contract to develop the Habitation and Logistics Outpost (HALO) for Gateway, which will be a critical way station and outpost in orbit around the Moon as part of NASA’s Artemis program.
NASA and its commercial and international partners are building Gateway to support science investigations and enable surface landings at the Moon, which will help prepare astronauts for future missions to Mars.
The firm, fixed-price contract is valued at $935 million. Under the contract, Northrop Grumman will be responsible for attaching and testing the integrated HALO with the Power and Propulsion Element (PPE), being built by Maxar Technologies. Northrop Grumman will also lead the integrated PPE and HALO spacecraft turnover and launch preparation with SpaceX, and support activation and checkout of HALO during the flight to lunar orbit. NASA is targeting November 2024 to launch the integrated spacecraft on a SpaceX Falcon Heavy rocket.
“NASA is building the infrastructure to expand human exploration further out into the solar system than ever before, including Gateway, the lunar space station that will help us make inspirational scientific discoveries at and around the Moon. Just as importantly, these investments will help NASA carry out the United States’ horizon goal: to further develop and test the technology and science needed for a human trip to Mars,” said NASA Administrator Bill Nelson. “The HALO is a critical component of Gateway, and this exciting announcement today brings us one step closer to landing American boots on both the Moon and Mars.”
HALO is where astronauts will live and conduct research while visiting the Gateway. The pressurized living quarters will provide command and control systems for the lunar outpost, and docking ports for visiting spacecraft, such as NASA’s Orion spacecraft, lunar landers, and logistics resupply craft. The HALO module will serve as the backbone for command and control and power distribution across Gateway and will perform other core functions, including hosting science investigations via internal and external payload accommodations and communicating with lunar surface expeditions. HALO also will enable the aggregation of additional habitable elements to expand Gateway capabilities. Immediately after launch, the Heliophysics Environmental and Radiation Measurement Experiment Suite, built by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will begin conducting research outside of the integrated spacecraft.
Zitat China’s Chang’e-5 orbiter is heading back to the moon
by Andrew Jones — September 6, 2021
The Chang’e-5 orbiter module which facilitated China’s complex lunar sample return last year is on its way to the moon following deep space tests.
The orbiter, one of four distinct Chang’e-5 mission spacecraft, delivered a return module containing 1.731 kilograms of lunar samples to Earth Dec. 16 before firing its engines to deep space for an extended mission.
The Chang’e-5 orbiter later successfully entered an intended orbit around Sun-Earth Lagrange point 1, roughly 1.5 million kilometers, in March. There it carried out tests related to orbit control and observations of the Earth and Sun.
New data from satellite trackers now suggests Chang’e-5 has left its orbit around Sun-Earth L1 and is destined for a lunar flyby early September 9 Eastern time.
It was noted that Chang’e-5 may have altered its orbit Aug. 30 based on observations by and data from amateur satellite trackers Daniel Estevez and Scott Tilley and independent astronomy software developer Bill Gray.
The spacecraft is under the control of the Beijing Aerospace Flight Control Center (BACC), which is responsible for telemetry, tracking and command of spacecraft. BACC has not yet provided an update on the plans for Chang’e-5.
Potential maneuvers such as entering lunar orbit, heading for another Sun-Earth Lagrange point or an Earth-moon Lagrange point depend on how much propellant the orbiter has remaining. Another possibility could be using the flyby to set Chang’e-5 on a trajectory to flyby 469219 Kamoʻoalewa, a quasi-satellite of Earth and the target for China’s 2024 near Earth asteroid sample-return mission.
Zitat von Andrew Jones October 7, 2021China’s Chang’e 5 mission returned pieces of the Moon in a technological feat last year. Now, scientists are publishing the first analyses of those samples.
Analysis of lunar material delivered to Earth by China’s Chang’e 5 mission confirms that the samples are the youngest collected to date. But their composition surprised scientists.
A team of lunar scientists led by Xiaochao Che (Chinese Academy of Geological Sciences) analyzed the lead content in two basalt fragments of around 3 to 4 millimeters in size, publishing the results in the October 8th Science. They determined the fragments’ to be around 1.96 billion years old, making them almost a billion years younger than material returned by the Apollo and Soviet-era Luna missions as well as what’s found in lunar meteorites.
The composition of the samples poses new questions, however.
A relatively high abundance of heat-producing elements in the lunar mantle, deep below the mare, might have kept the magma flowing. Some of these elements would have been radioactive (namely uranium, thorium, and potassium). Yet Che’s team finds no unusual amounts of these radioactive elements; the concentrations are similar to those the basalts returned by Apollo and Luna missions.
Scientists also expected the rocks from this site to contain other heat-producing materials known as KREEP, short for potassium (labelled “K” in the periodic table), rare Earth elements, and phosphorus. Instead, only relatively small amounts were found.
“The unexpected composition challenges our traditional thinking,” says Long Xiao (China University of Geosciences), a planetary geoscientist not involved in the study. If not heat-producing elements, what would have kept Oceanus Procellarum hot? Did the tidal pull from Earth’s gravity heat the Moon’s interior? Or is the mantle made up of different minerals than we thought?
Besides raising new questions, the results also provide clarity in chronology. The age of Oceanus Procellarum gives a “ground truth” that scientists can compare to the number of craters there. They can then infer the ages of other surfaces across the solar system by measuring the crater density.
Observations from lunar orbit had identified this mare to be younger than other areas by its paucity of craters, which suggested that the lava there had flowed more recently. By dating the samples returned to Earth, the scientists confirm that volcanism occurred later in Oceanus Procellarum than other areas of the Moon.
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