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(25 September 2020 – DLR) The Chang’e-4 lunar lander touched down on the far side of the Moon on 3 January 2019, with a German instrument for measuring space radiation on board.

Since then, the Lunar Lander Neutron and Dosimetry (LND) instrument has been measuring temporally resolved cosmic radiation for the first time. Earlier devices could only record the entire ‘mission dose’. In its current issue, the scientific journal Science Advances reports on the work of the international group of scientists involved with the LND, including researchers from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). Their investigations have involved more precise radiation measurements on the Moon.

Chang’e-4 lunar lander imaged by the Yutu-2 rover (courtesy: CNSA/CLEP/NAOC)

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Lunar Lander Neutron and Dosimeter (LND) instrument (courtesy: Stefan Kolbe, CAU)

“Over the coming years and decades, various nations are planning to send crewed missions to explore the Moon. Space radiation poses a significant risk to the health of humans. The Apollo astronauts carried radiation measuring devices, referred to as dosimeters, on their bodies. But these only determined the radiation exposure over the course of the entire mission,” says Oliver Angerer, LND Project Manager at the DLR Space Administration. With the LND instrument it is possible to measure the various characteristics of the radiation field over time intervals of one, 10 or 60 minutes. This enables researchers to calculate the ‘equivalent dose’, which is important for estimating biological effects.

High radiation exposure in a spacesuit

DLR radiation physicist Thomas Berger from the DLR Institute of Aerospace Medicine, who participated in the publication explains: “The radiation exposure we measured is a good indication of the radiation inside a spacesuit. The measurements give us an equivalent dose rate – the biologically weighted radiation dose per unit of time – of around 60 microsieverts per hour. For comparison, during a long-haul flight from Frankfurt to New York, the dose rate is five to 10 times lower than this. On Earth’s surface, it is some 200 times lower. In other words, a long-term stay on the Moon will expose astronauts’ bodies to high doses of radiation.”

“Human bodies are simply not made to be exposed to space radiation,” adds Robert Wimmer-Schweingruber of the Christian-Albrecht University (CAU) in Kiel, whose team developed and built the LND instrument . “On longer missions to the Moon, astronauts will have to protect themselves from it – by covering their habitat with a thick layer of lunar rock, for example. This could reduce the risk of cancer and other illnesses caused by long periods of time spent on the Moon.”

The instrument developed in Kiel conducts measurements throughout the lunar day, but like all other scientific devices on the lander, remains switched off throughout the extremely cold, approximately two-week lunar night, to save power. The instrument and lander were designed to conduct their measurements for at least one year – a target they have already surpassed. The data from the LND and the lander are transmitted to Earth via the relay satellite Queqiao (‘Magpie Bridge’), which is located above the far side of the Moon.

Astronautical space exploration on the Moon and beyond

The radiation data are also relevant for future interplanetary missions. Since the Moon has neither a protective magnetic field nor an atmosphere, the radiation field on the Moon’s surface is similar to that in interplanetary space. “With that in mind, the LND measurements are also used to develop computer models to calculate the expected radiation exposure, refine our models and thus contribute towards our work on radiation protection for astronauts on future missions. It is vital that the detector also allows conclusions to be drawn about the composition of the radiation field, such as how many neutrons and high energy-charged particles are present,” explains Berger.

Funding

The Lunar Lander Neutron and Dosimetry (LND) instrument was developed and built at the Christian-Albrecht University of Kiel on behalf of the DLR Space Administration with funding from the German Federal Ministry of Economic Affairs and Energy (Bundesministerium für Wirtschaft und Energie; BMWi). The research conducted by the DLR Institute of Aerospace Medicine is supported by the Moon and Mars Exploration Studies (MoSES) project, which is part of DLR’s Space Exploration Programme.

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OSIRIS-REx In the midst of sample stowage

OSIRIS REx In the midst of sample stowage

(28 October 2020 – NASA Goddard) Yesterday, NASA’s OSIRIS-REx mission successfully placed the spacecraft’s sample collector head into its Sample Return Capsule (SRC).

(courtesy: NASA)

The first image shows the collector head hovering over the SRC after the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) arm moved it into the proper position for capture. The second image shows the collector head secured onto the capture ring in the SRC. Both images were captured by the StowCam camera.

Today, after the head was seated into the SRC’s capture ring, the spacecraft performed a “backout check,” which commanded the TAGSAM arm to back out of the capsule. This maneuver is designed to tug on the collector head and ensure that the latches – which keep the collector head in place – are well secured. Following the test, the mission team received telemetry confirming that the head is properly secured in the SRC.

Before the sampler head can be sealed into the SRC, two mechanical parts on the TAGSAM arm must first be disconnected – these are the tube that carried the nitrogen gas to the TAGSAM head during sample collection and the TAGSAM arm itself. Over the next several hours, the mission team will command the spacecraft to cut the tube and separate the collector head from the TAGSAM arm. Once the team confirms these activities have executed as planned, they will command the spacecraft to seal the SRC.

StowCam, a color imager, is one of three cameras comprising TAGCAMS (the Touch-and-Go Camera System), which is part of OSIRIS-REx’s guidance, navigation, and control system. TAGCAMS was designed, built and tested by Malin Space Science Systems; Lockheed Martin integrated TAGCAMS to the OSIRIS-REx spacecraft and operates TAGCAMS.

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Rocket Lab successfully launches 15th mission, deploys satellites for Planet, Canon Electronics

Rocket Lab successfully launches 15th mission deploys satellites for Planet

(29 October 2020 – Rocket Lab) Rocket Lab has successfully launched its 15th Electron mission and deployed Earth-imaging satellites for Planet and Spaceflight Inc. customer Canon Electronics.

The mission was Rocket Lab’s fifth for this year, making Electron the second-most frequently flown U.S. launch vehicle in 2020.

(courtesy: Rocket Lab)

The ‘In Focus’ mission launched from Rocket Lab Launch Complex 1 on New Zealand’s Māhia Peninsula at 21:21 UTC, 28 October 2020. The Electron launch vehicle successfully deployed ten commercial small satellites to a 500km circular orbit, bringing the total number of payloads deployed by Rocket Lab to 65.

The payloads on ‘In Focus’ included the latest flock of Planet’s Earth-imaging SuperDove small satellites, each integrated with and deployed from Rocket Lab’s Maxwell satellite dispensers. Flock 4e’ bolsters Planet’s constellation of Earth-observation satellites already on orbit providing medium-resolution global coverage and near-daily revisit. Canon Electronic’s mission objective with their CE-SAT-IIB microsatellite is to demonstrate the company’s Earth-imaging capability with a middle-size telescope equipped with an ultra-high sensitivity camera to take night images of the Earth and small size telescopes suitable for CubeSat use.

“Congratulations to Planet on the addition of their latest SuperDoves to their constellation and to the team at Canon Electronics on the deployment of their latest tech demonstration satellite,” said Rocket Lab founder and CEO, Peter Beck. “Electron has once again delivered a smooth ride to orbit and precise deployment for our individual rideshare customers. Continuing to launch in the face of global disruption and adversity, while at the same time becoming the second-most frequently flown U.S. launch vehicle this year, is the latest display our dedication in providing ongoing, easy access to space for our customers.

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OSIRIS-REx spacecraft collects significant amount of asteroid

OSIRIS REx spacecraft collects significant amount of asteroid

(23 October 2020 – NASA) Two days after touching down on asteroid Bennu, NASA’s OSIRIS-REx mission team received on Thursday, Oct. 22, images that confirm the spacecraft has collected more than enough material to meet one of its main mission requirements – acquiring at least 2 ounces (60 grams) of the asteroid’s surface material.

The spacecraft captured images of the sample collector head as it moved through several different positions. In reviewing these images, the OSIRIS-REx team noticed both that the head appeared to be full of asteroid particles, and that some of these particles appeared to be escaping slowly from the sample collector, called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) head. They suspect bits of material are passing through small gaps where a mylar flap – the collector’s “lid” – is slightly wedged open by larger rocks.

Captured by the spacecraft’s SamCam camera on Oct. 22, 2020, this series of three images shows that the sampler head on NASA’s OSIRIS-REx spacecraft is full of rocks and dust collected from the surface of the asteroid Bennu. They show also that some of these particles are slowly escaping the sampler head. Analysis by the OSIRIS-REx team suggests that bits of material are passing through small gaps where the head’s mylar flap is slightly wedged open. The mylar flap (the black bulge on the left inside the ring) is designed to keep the collected material locked inside, and these unsealed areas appear to be caused by larger rocks that didn’t fully pass through the flap. Based on available imagery, the team suspects there is plentiful sample inside the head, and is on a path to stow the sample as quickly as possible. (courtesy: NASA)

“Bennu continues to surprise us with great science and also throwing a few curveballs,” said Thomas Zurbuchen, NASA’s associate administrator for science at the agency’s headquarters in Washington. “And although we may have to move more quickly to stow the sample, it’s not a bad problem to have. We are so excited to see what appears to be an abundant sample that will inspire science for decades beyond this historic moment.”

The team believes it has collected a sufficient sample and is on a path to stow the sample as quickly as possible. They came to this conclusion after comparing images of the empty collector head with Oct. 22 images of the TAGSAM head after the sample collection event.

The images also show that any movement to the spacecraft and the TAGSAM instrument may lead to further sample loss. To preserve the remaining material, the mission team decided to forego the Sample Mass Measurement activity originally scheduled for Saturday, Oct. 24, and canceled a braking burn scheduled for Friday to minimize any acceleration to the spacecraft.

From here, the OSIRIS-Rex team will focus on stowing the sample in the Sample Return Capsule (SRC), where any loose material will be kept safe during the spacecraft’s journey back to Earth.

“We are working to keep up with our own success here, and my job is to safely return as large a sample of Bennu as possible,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson, who leads the science team and the mission’s science observation planning and data processing. “The loss of mass is of concern to me, so I’m strongly encouraging the team to stow this precious sample as quickly as possible.”

The TAGSAM head performed the sampling event in optimal conditions. Newly available analyses show that the collector head was flush with Bennu’s surface when it made contact and when the nitrogen gas bottle was fired to stir surface material. It also penetrated several centimeters into the asteroid’s surface material. All data so far suggest that the collector head is holding much more than 2 ounces of regolith.

OSIRIS-REx remains in good health, and the mission team is finalizing a timeline for sample storage. An update will be provided once a decision is made on the sample storage timing and procedures.

NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace of Tempe, Arizona, are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

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