For the last 16 months, Curiosity been engaged is studying “Vera Rubin Ridge”. Originally seen as a measn for the rover to traverse from one area of interest on “Mount Sharp” to another, the ridge became a point of interest itself when the rover imaged a rock formation that could fill a gap in the science team’s knowledge about the mound’s formation.
At the time the rock formation was noticed, engineers had been in the process of trying to overcome a issue with the rover’s drill that had prevented its use for several months. A potential work-around had been tested on Earth, so investigation of the rock formation offered the opportunity to test the updated drilling approach. Curiosity was therefore ordered to reverse course in the hope the tests would be successful and a sample of the rock could be gathered.
While successful, this was actually complicated – the issue with the drill feed mechanism also meant that the usual means of sorting samples post extraction had to be abandoned in favour of a new approach. However, the initial success meant Curiosity could resume drill-based sample gathering and analysis, marking the start of period of exploration around the ridge area – albeit it one interrupted by the 2018 global dust storm. In December 2018, this work concluded with the rover collecting its 19th overall sample on Mars, at a location on the ridge called “Rock Hall”.
Since then, the rover has been completing its work on the ridge, which included taking a “selfie” on January 15th, comprising 57 individual images taken with the Mars Hand Lens Imager (MAHLI) camera on the end of its robotic arm. At the ed of January, Curiosity said farewell to “Vera Rubin Ridge”, resuming its traverse southward towards the “clay bearing unit” it was originally heading to when it stopped at the ridge in September 2017.
At the same time, the science team for the rover released a paper revealing a new mystery about “Mount Sharp” and showing how instruments aboard the rover were re-purposed to allow it to be made.
As I’ve previously reported, previous studies of “Mount Sharp”- more correctly called Aeolis Mons, the 5 km (3 mi) high mound at the centre of the crater – suggested it was formed over two billions years, the result of repeated flooding of the crater laying down bands of sedimentary deposits, some of which were blown away by wind action, others of which settled. Over the millennia, these layers were sculpted by wind action within the crater, until only the central mound was left.
However, this type of water-induced layering should have resulted in the lower slopes of Mount Sharp being heavily compressed; but measurements of the local gravity environment of the terrain Curiosity has been driving over in its ascent up “Mount Sharp”, indicate the layers of the lower slopes are less dense than thought, meaning it is relatively porous. This indicates they were not buried under successive layers as had been thought, and thus some other process must have given rise to the mound.
The measurements were obtained by re-purposing the accelerometers Curiosity uses as a part of its driving / navigation system. Normally, these are used to determine its location and the direction it is facing with enormous precision. But, through a subtle piece of reprogramming, engineers were able to turn them into a gravimeter, allowing Curiosity to measure local gravity every time it stopped driving, and with massively greater precision than can be achieved from orbit.
Given the results tend to dispel the idea that water action was primarily responsible for filling the crater with sediments subsequently added to and shaped by wind action, it’s been proposed that “Mount Sharp” has been formed almost entirely as a result of Aeolian (wind-driven) sedimentation. This would leave the layers forming the mound a lot less dense in comparison to layers laid down and built up as a result of water action and settling.
However, this doesn’t entirely explain why the mount was formed, and further study is required before it can be said with certainty that wind played the core part in building and sculpting “Mount Sharp”. In the meantime, the re-purposing of Curiosity’s accelerometers is another example of the flexibility found within NASA’s robot explorers, as Ashwin Vasavada, Curiosity’s project scientist, noted in response to the new information.
There are still many questions about how Mount Sharp developed, but this paper adds an important piece to the puzzle. I’m thrilled that creative scientists and engineers are still finding innovative ways to make new scientific discoveries with the rover.
– Ashwin Vasavada, Curiosity’s project scientist.
New Plan to Contact Opportunity
It is now seven months since communications with NASA’s other operational Mars rover, Opportunity, was lost as a result of the planet girdling dust storm that ran from late May until around the end of July 2018, and which forced the rover to go into a power saving safe mode as there were insufficient sunlight for its solar cells to recharge its batteries.
In late August, ith the skies over Opportunity clearing of dust, NASA initiated an attempt to nudge “Oppy” into trying to resume contact with mission control using what is called the “sweep and beep” method. This involved sending a series of wake up commands throughout the day, then listening for the “beep” signal that would indicated “Oppy” had received the signal and was once again awaiting commands, allowing attempts at recovery to commence. Unfortunately, this has not been the case.
Originally, it had been intended that if no response was received in 45-day period, NASA would switch to a purely passive means of listening out for “Oppy” in the hope the rover might send a message. But on January 25th, 2019, the space agency indicated they would be taking a different tack.
The new approach means that the “sweep and beep” approach will be continued, but slightly differently. In order to account for the possibility that Opportunity has both and off-kilter clock and both of its primary X-band communications systems, the outward commands designed to nudge a simple “beep” response from the rover will be replace by a command for it to switch away from using its primary communications system(s) to it secondary, the hope being that it would allow the rover to respond, and enable a more detail assessment of Opportunity’s condition to be made.
This effort is expected to continue for “several weeks” before NASA will again reassess the likelihood of re-establishing contact with the rover. However, a new threat is in the offing for Opportunity as winter starts to settle in the hemisphere where it is operating; if its solar panels are not working efficiently, the exceptionally low winter temperatures could damage it beyond recovery.
Orion Span: Funding Goal Missed
In April 2018, I wrote about a start-up company called Orion Span. Founded by entrepreneur Frank Bunger, the company stated it planned to offer a “full astronaut experience” aboard a single-module orbital facility called Aurora Station, starting in 2022. At the time of that Space Sunday report, I noted:
It’s a pretty bold statement for a start-up to make, particularly as Orion Span claims just six employees at present. Developing, testing and launching a crew-capable orbital facility generally takes many years to achieve. not only is there the actual design and fabrication, there’s all of the required testing and certification, etc; so aiming to do so in just 3 or 4 years is a little heady. Further, Bunger claims the company can develop the initial module for “tens of millions” of dollars – that’s considerably less than the cost of many satellites.
Bunger claimed the company would raise its financing through the use of “proprietary technology” and business arrangements – although no details were released on precisely what any of this would be. However, in December, Orion Span did reveal part of its strategy: using the SeedInvest crowdfunding site to try to raise US $2 million.
SeedInvest is a platform that allows funds to be raised in return for equity in a company, with a minimum funding level of US $1,000 per investor. This attempt closed on January 25th, 2019, and – unsually – the Orion Span campaign page was removed from SeedInvest shortly after. However, the Wayback Machine shows it raised less than one-eighth of the funding goal: US $235,700.
The crowdfunding effort was part of was part of a two-stage investment round which also utilised the more usual Regulation D funding in what is called a “combined offering”. However, for any funding to be achieved, the crowdfunding offering (referred to as a Regulation CF offering) must gain at least US $25,000 in secured investment offers, and the Regulation D offering must obtain at least US $1 million. Failure to achieve either means all investment commitments are cancelled, and committed funds returned. The Regulation D offering closed at the end of January 2019, and thus far Orion Space has refused to disclose whether or not it has crossed the US $1 million threshold.
A Lunar Mystery
Chang’e 4 and Yutu 2, China’s lander and rover combination that are exploring an area of the south regions of the far side of the Moon, have awoken from their 2-week “overnight” sleep to report a mystery. Data received from both indicate that the overnight temperatures, with the far side of the Moon out of direct sunlight, plummeted to -190oC (-310oF). That’s about 17oC lower than the typical “night-time” temperatures recorded on the lunar near side by the various missions that have landed there.
When this should is unclear; it have been thought that the surface material on the Moon was relatively uniform, and thus would result in similar temperatures being recorded. However, the Chang’e 4 / Yutu 2 data suggests there is something different in the composition of the far side regolith that causes it to retain less heat than is the case with the side of the Moon facing Earth – although what that might be is as yet unknown.
Israel To Be Next to Reach the Moon
2019 should see another nation join the exclusive ranks of those who have landed mission on the surface of the Moon, with the arrival of SpaceIL’s Beresheet lander. It will also hopefully mark the first privately funded mission to reach the Moon.
An Israeli organisation, SpaceIL originally developed Beresheet (Hebrew for “Genesis” or “In the Beginning”) for the Lunar X-Prize contest, as a means to promote scientific and technological education in Israel. After the Lunar X-Prize was cancelled, work continued on the 600 kg lander, which is now in the United States undergoing preparation for launch.
Largely funded through private donations (some US $7.5 million was provided by the Israeli Space Agency), Beresheet is due to be launched on a Falcon 9 rocket on February 18th, 2019. As the primary payload for this launch is a satellite intended for geostationary orbit, Beresheet will not be sent directly to the Moon as is usually the case. Instead, it will be placed in Earth orbit, and over a period of around 10 weeks, will increase that orbit until it reaches a point where the Moon’s gravity takes over.
At that point, the lander will spend two weeks manoeuvring itself into the correct lunar orbit in order to make a descent to a landing site close to Mare Serenitatis (the Sea of Serenity), a region previously visited by Apollo 17 and Russia’s Luna 21.
I’ll have more on this mission closer to the launch date.