GRACE-FO resumes data collection

The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission has resumed collecting science-quality data and planned in-orbit checks after successfully completing a switchover to a backup system in the microwave instrument (MWI) on one of the mission's twin spacecraft. The in-orbit checks include calibrations and other system tests, and are expected to continue until January, when GRACE-FO will enter the science phase of its mission. "The new unit is performing as expected," said Frank Webb, GRACE-FO project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "The spacecraft are tracking each other and collecting science-quality data." Both GRACE-FO satellites are equipped with redundant systems in their MWIs, which are their primary measurement instruments. The MWIs very precisely measure the distance change between the two satellites. The switchover to the backup system was required after an anomaly occurred in a component of the primary system. The primary unit was powered down on July 19, when an instrument fault monitor detected that it was using less current than expected. After a full investigation by an anomaly response team, the mission team began a series of procedures required to switch over to the new unit. The backup system in the MWI was powered up on Oct. 19.

The primary science objective of GRACE-FO - like that of its predecessor GRACE, which operated from 2002 to 2017 - is to track how water is redistributed on Earth by producing highly accurate, monthly gravity field maps.

Measurements of changes in Earth's gravity field provide measurements of mass change and enable unique insights into Earth's changing climate, Earth system processes like droughts and sea level changes, and the impacts of human activities on water resources.

Thrusters with additively manufactured components qualified to fly humans on Orion spacecraft

Aerojet Rocketdyne recently completed qualification testing for the enhanced reaction control thruster system for NASA's Orion crew vehicle, helping to clear the way for the Lockheed Martin-built spacecraft's second test flight, and first mission to cislunar space, called Exploration Mission-1 (EM-1). The reaction control system, or RCS, is the only means of guiding the Orion crew module after it separates from its service module in preparation for atmospheric re-entry and subsequent splashdown. Consisting of 12 MR-104G hydrazine thrusters capable of 160 pounds of thrust each, the system also will ensure that the spacecraft is properly oriented (with its heat shield pointed downward) for re-entry, and stable during descent. Aerojet Rocketdyne employed cutting-edge additive manufacturing processes, also known as 3-D printing, in fabricating the RCS engine nozzle extensions. These 3-D printed components, along with other items on the spacecraft, mark one of the first times in history that a spacecraft carrying humans will incorporate additively manufactured parts. "Additive manufacturing eliminates traditional design constraints, as well as reduces manufacturing times," said Eileen Drake, Aerojet Rocketdyne CEO and president. "Our use of 3-D printing on Orion is just one example of how we are incorporating this breakthrough technology across our portfolio of propulsion products."

During the yearlong qualification test program at Aerojet Rocketdyne's Redmond, Washington, facility, a single engine was subjected to shock and vibration, exceeding the maximum stresses expected during the upcoming EM-1 launch.

For EM-1, Orion will be launched toward the Moon on the maiden flight of NASA's Space Launch System (SLS) rocket. The non-flight test engine - drawn from the same production lot as the EM-1 RCS flight engines - burned through 619 pounds of propellant during the test program, accumulating 962 seconds of total firing time.

"Following our rigorous qualification testing program, we're confident that this enhanced RCS system is ready to fly," added Drake. "The reaction control thrusters are critical to the Orion capsule's safe return to Earth at the completion of EM-1 as well as future crewed missions."

The EM-1 RCS thruster design builds on the flight proven engine demonstrated on the Exploration Flight Test-1 mission in 2014. The enhanced system features a stronger structure, increased resistance to thermal stresses and reduced mass. The improved manufacturing process updated the system to account for changed loads and to ultimately increase affordability.

On EM-1 an uncrewed Orion spacecraft will launch into a distant retrograde orbit around the Moon before returning to Earth for a splashdown in the Pacific Ocean. It will be followed by EM-2, during which Orion will fly near the Moon with astronauts on board.

In addition to the RCS, Aerojet Rocketdyne is supplying the main- and upper-stage liquid engines for the SLS, and well as the jettison motor that will separate Orion's launch abort system from the crew module shortly after activation of the SLS's second stage.

The company also is supplying the auxiliary thrusters for Orion's European Service Module (ESM), and supported a NASA-led effort to modify a Space Shuttle OMS-E engine, originally built by Aerojet Rocketdyne for its new application as the ESM main maneuvering engine.

Water cycle along the northern rim of Hellas Basin throughout Mars' history

The northeastern rim region of Hellas impact basin, located in the southern hemisphere of Mars, contained numerous ephemeral lakes throughout Mars' history, a new study reveals. A new paper published in Astrobiology examines a region where depressions may have been hosted ponding water that originated from different sources, including precipitation, fluvial transportation and ground water. Sediments partially filled the depressions or formed fan shaped deposits within these paleolakes. Some of these paleolakes formed in fresh to degraded impact craters, others were situated in depressions of rolling terrain - paleolakes are lakes that existed at a time when the climate where it was located was different than today. The paper's authors are Henrik I. Hargitai, who conducted the research while at NASA Ames Research Center; Virginia C. Gulick, SETI Institute; and Natalie H. Glines, SETI Institute. The candidate paleolakes are identified along drainage systems that emptied into smaller depressions at the margin of Hellas Planitia, the largest and oldest impact basin on the surface of Mars, terminating in almost the same elevations along a 250 km long line."We have found several groups of paleolakes with different geologic histories along each drainage system", the authors explain. Some paleolake groups served as the source of km-wide, hundreds of km long channel systems, while others formed through-flowing, or terminal lakes. "Some of the inlet channels and their deposits are similar to those produced by flash floods" the lead author, H. Hargitai explains.

"Some of these flood discharges may even have been catastrophic in magnitudes (~ several 105 - 106 m3/s) similar to those that formed the Channeled Scablands in eastern Washington state, while the morphology of other channels and valleys suggest much lower, longer duration discharges more like those of the Mississippi River", co-author Gulick added.

"These hundreds-of-meters wide channels cut across widespread ash-laden volcanic lava and impact debris terrains across the interior slope of Hellas basin".

Through-flowing lakes are identified from two connecting channels, one inlet, and another outlet. Minor inlet channels in these sites suggest that these lakes were filled by ground water and provided only a minor water discharge on the surface. Other lakes may have been filled during occasional floods and several impact crater lakes were identified as fed precipitation, likely in the form of snow.

One terminal impact crater paleolake is nearly filled with smooth sediment, which is similar to that found in the salars (saline lakes) in the Andes mountain region of Patagonia. This similarity suggests that conditions on Mars may have been comparable to those at the high-elevation, cold and arid Andes region at the time when those lakes formed.

The list of 34 new candidate Martian paleolakes were compiled from a detailed hydrogeographic analysis of the Northeast Hellas region, where only one impact crater paleolake had been previously identified.

This suggests that Mars was hydrologically much more active than previously recorded and that some regions hosted numerous lakes periodically throughout Mars' history. The lakes were fed by different hydrological processes, likely related to recurring hydrothermal activity from nearby volcanoes Hadriaca and Tyrrhena Paterae.

Small rockets are taking off

In mid-November, a company called Rocket Lab will try to send six small satellites into orbit around Earth -- a fairly banal undertaking, save for the size of the launch rocket. It is only 17 meters (56 feet) tall and 1.2 meters (four feet) in diameter. And if all goes well, the US company will send up more than one of its Electron rockets every month in 2019. Rocket Lab, which was created in 2006, completed a successful test flight in January and is expected this month to be the first of a new generation of companies to declare itself operational in the so-called "small launch industry." The launch window opens on November 11. Barring a mishap, or another delay after a months-long technical setback, the rocket will blast off from the world's first private orbital launch range in Mahia, New Zealand. Like Rocket Lab, dozens of start-up companies are developing rockets adapted to send small, micro or nanosatellites -- which weigh anything from a few kilos to a few hundred kilos (pounds) -- into space. It's a whole new chapter for the "New Space Race," the latest industry revolution begun about a decade ago and based on private, not public, innovation -- especially in the United States. Rocket Lab's creation has a black carbon composite fuselage with "Electron" emblazoned on the side in white lettering. Its engine is produced by a 3D printer in California, a move that helped cut costs, the company's chief financial officer Adam Spice told AFP.

Launching from New Zealand also has its advantages over traditional sites in Florida or California: there are not nearly as many planes in the air.

"If you've got no air traffic to clear, we have the ability to launch more frequently than any other place in the planet," Spice noted.

The company has six Electron rockets in production, and is estimating it will carry out 16 launches next year.

- 'A lot more flexibility' -

Rocket Lab's plans are not going to be cheap -- relatively, its rocket is expensive on a per-kilo basis.

But it's holding out the prospect of frequent launches that would help resolve the current backlog.

Nowadays, companies that want to put a small satellite into space are only offered spare space in a rocket launched by SpaceX or Arianespace, which are primarily reserved for bigger, costlier satellites.

The two-stage Falcon 9 operated by Elon Musk's SpaceX is 70 meters tall (more than four times bigger than the Electron) and can carry 23 tons of cargo into space (as opposed to a maximum of 250 kilos for the Electron).

But small rockets should help reduce launch wait times from 18-24 months or more, at the bigger companies, to a mere six months.

Customers are ready to pay for the speedy service: the going rate at Rocket Lab is about $40,000 a kilo, as compared with $3,000 a kilo at SpaceX.

"What you have with the small launch vehicles is you get a lot more flexibility," said Rob Coneybeer, an investor in Vector, one of Rocket Lab's competitors.

Other companies in the small rocket sector include Virgin Orbit, Stratolaunch, and Australia-based Gilmour.

Chad Anderson, the CEO of the Space Angels investment network, says there are about 180 companies working on small rockets.

But, he told AFP, there are only about a dozen worldwide that actually have hardware. And even fewer have the necessary funding.

"Maybe there's like half a dozen that are really credible at this moment," the investor said.

- Numerous applications -

The success of those half-dozen firms will help define how fast the New Space Race shakes out.

In 2009, when SpaceX sent its first satellite into orbit, there were about a dozen private space companies, according to Anderson.

Today, there are more than 375 such firms, which have raised more than $16 billion in funding.

The applications for the technology are numerous -- first of all, in telecommunications, and then in Earth observation, according to participants in the second Space Summit organized by The Economist in New York on Thursday.

Obtaining more precise images of Earth, more frequently, would be something companies in multiple sectors would want, from defense to farming, insurance and finance.

Such satellites could help facilitate everything from repairing gas pipelines to assessing flood damage, for example.

SpaceKnow is already using them to count parked cars at Disney World in Florida or the number of swimming pools in Brazil, as well as to observe activity at 6,000 factories in China.

Such data is scooped up by clients on Wall Street, who use it as a new kind of economic indicator.

For all of these services to be accommodated, more satellites need to be in orbit, and thus more rockets need to be launched. Nearly a decade after the creation of SpaceX, the path to space is getting wider.

NASA conducts a 'BOO-tiful' RS-25 engine test

NASA delivered a treat with a full-duration RS-25 engine test Oct. 31, and the shake, rattle and roar of the hot fire kept away any eerie creaks and frightful sounds the Halloween day might have had to offer. A team of NASA, Aerojet Rocketdyne and Syncom Space Services operators conducted the 500-second RS-25 test on the A-1 Test Stand at Stennis Space Center near Bay St. Louis, Miss., the fifth hot fire in an engine test series that began in mid-August. The test marked an acceptance hot fire of another RS-25 engine controller for use on a future flight of NASA's new Space Launch System (SLS) rocket, which is being built now to carry humans deeper into space than ever before. The new flight controller serves as the RS-25 "brain," helping the engine communicate with the rocket and controlling engine operation and internal health diagnostics. The recent RS-25 test series also features a 3D-printed pogo accumulator, used to dampens pressure oscillations that can cause flight instability, and an innovative main combustion chamber, fabricated using a new hot isostatic pressing (HIP) bonding technique that saves considerable time and money. NASA has been testing RS-25 engines at Stennis since 2015 to ensure they will perform as needed for SLS, which will be the most powerful rocket in the world. Four RS-25 engines, firing simultaneously, will provide a combined 2 million pounds of thrust to help launch the new rocket. The engines will fire in conjunction with a pair of solid rocket boosters; altogether, SLS will launch with more than 8 million pounds of thrust.

The RS-25 engines to be used on initial SLS missions are former space shuttle main engines, modified to provide additional power. Through the shuttle years, the engines were modified to provide additional thrust up to 109 percent of the original designated level.

SLS will also evolve to a larger, more powerful rocket, and engines are being modified again to operate at 111 percent of their original power level for additional performance. In addition to its RS-25 hot fires, NASA is preparing to test the core stage for the first SLS mission on the B-2 Test Stand at Stennis.

The test will involve installing the flight core stage on the renovated stand and firing its four RS-25 engines simultaneously, like during an actual launch. RS-25 engines are important for powering the SLS as NASA leads a return to the Moon through an innovative and sustainable program of exploration to expand human presence into the solar system.

Beginning with Exploration Mission-1, SLS and Orion will demonstrate the critical backbone capabilities that will carry humans to the Moon and farther into space than ever before on a variety of missions with increasing complexity.

SLS's unprecedented power and volume will also carry the large pieces of hardware needed to build the Gateway and other long-term infrastructure at the Moon and later, for human missions to Mars. Aerojet Rocketdyne is the RS-25 engine prime contractor. Syncom Space Services is the prime contractor for Stennis facilities and operations.