Space Sunday: Mars, Uranus and Neptune

The ExoMars Rover Rosalind Franklin, 2018. Cedit: EADS Astrium UK

It’s been a mission almost 20 years in the making, but it finally has a vehicle name: the European Space Agency’s (ESA) ExoMars rover is now officially called Rosalind Franklin.

In 2001, ESA announced the goal of landing a large rover vehicle on Mars in 2009 as a part of its Aurora programme for the human exploration of the Red Planet. As an optional programme, Aurora allowed ESA member states to determine which elements they would like to support. In 2005, the UK’s EADS Astrium indicated it would undertake the design and construction of the rover, then referred to as ExoMars.

Over the next decade plus, ExoMars as a whole underwent numerous changes in scope and capability. Some of these changes were driven from within ESA. For example, in order to meet initial launch requirements using a Russian rocket, the rover was scaled down to just 180 kg. However, this left it was just 6 kg for the science payload, prompting a move to using a more powerful Ariane launcher, allowing for a larger rover and science payload – but at twice the price of a Russian launch.

Other changes came about through external influences. In 2009, ESA signed an agreement with America’s NASA, which would have seen the a joint ESA / NASA mission, with the US agency taking responsibility for the rover (renamed the Mars Astrobiology Explorer-Cacher, or MAX-C) and ESA producing the lander and an orbiter – the Trace Gas Orbiter. Less than a year later, MAX-C was scrapped in favour (once again) of a large 600 kg European rover.

The ExoMars rover over the years. Top left: 2007 (credit: Jastrow). Bottom left: 2009 (credit: Mike Peel) and 2015 (credit: Cmglee)

Then in 2011 NASA withdrew from the agreement, forcing a further reassessment of the rover and the ExoMars project overall. In 2013, ESA and Russia’s Roscosmos signed an agreement that would see a revised ExoMars mission  – the rover and the Trace Gas Orbiter (TGO) – flown atop two uprated Proton rockets in 2016 and 2018, with the first launch featuring the TGO, which arrived in Mars orbit in October 2016. The second would be the rover mission, intended for launch in 2018.

The switch back to using a Russian launch vehicle meant the rover had to go through a further redesign in order to shed 290 kg of mass. By 2016, all of this left the ExoMars project breaking through its budget cap of €1 billion. In order to secure the required €1000 million needed to complete the project’s development and launch costs, the launch would have to be pushed back until 2020. It is currently slated for lift-off on July 25th, 2020 and arrive on Mars on March 19th, 2021.

Rosalind Franklin. Credit: Jewish Chronicle Archive / Heritage-Images

The rover’s name has been given in honour of Rosalind Elsie Franklin (July 25th, 1920 – April 16th, 1958), an English chemist and X-ray crystallographer who made contributions to the understanding of the molecular structures of DNA (deoxyribonucleic acid), RNA (ribonucleic acid), viruses, coal, and graphite. Although her works on coal and viruses were appreciated in her lifetime, her contributions to the discovery of the structure of DNA were largely recognised posthumously.

Her name was one of 36,000 submissions by citizens from all ESA Member States, following a competition launched by the UK Space Agency in July 2018. It was selected by a panel of experts before being officially announced by UK astronaut Tim Peake on Thursday, February 7th, 2019 at an event in Stevenage UK, where the rover has been built.

Rosalind Franklin is one of science’s most influential women, and her part in the discovery of the structure of DNA was truly ground-breaking. It’s fitting that the robot bearing her name will search for the building blocks of life on Mars, as she did so on Earth through her work on DNA.

– Alice Bunn, international director of the U.K. Space Agency

In a slight tweak on the usual convention – most spacecraft named in honour of a person are referred to by the individual’s last name – the rover is already being referred to simply as “Rosalind” (although in fairness, its prototypes and test units have also been known by first names, such as “Bruno”).

Once on Mars, the rover will be the first of its kind to combine the capability to roam around Mars and to study it at depth. To do this, it is equipped with a drill capable of reaching down two metres (6ft 6in) below the surface, gather samples for analysis using a set of instruments collective called the Pasteur Suite, searching for evidence of past – and perhaps even present – life buried underground, where water is known to be present and where harsh solar radiation cannot penetrate. In addition, the rover has a suite of instruments to study the atmosphere, examine the sub-surface environment with radar to locate areas to drill for samples, identify deposits of water ice, etc. Further, ESA is currently considering including a small “scout” rover, designed to identify areas of soft sand, etc., where Rosalind might get stuck trying to traverse.

Rosalind will be delivered to the surface of Mars by a 1.8 tonne landing platform built by Roscosmos. This will use a combination of parachutes and retro-rockets to achieve a soft landing. The current primary landing site for the rover is Oxia Planum, a large plain in the northern hemisphere of Mars, which contains one of the largest exposures of clay-bearing rocks on the planet which are roughly 3.9 billion years old. These are rich in iron-magnesium, indicating water played a role in their formation. The area comprises numerous valley systems with the exposed rocks exhibiting different compositions, indicating a variety of deposition and wetting environments, making it an ideal subject for exploration.

Hubble Reveals Dynamic Atmospheres of Uranus and Neptune

As well as studying deep space, the Hubble Space Telescope routinely keeps its eye on the planets of the solar system. In doing so, it has uncovered a new mysterious dark storm on Neptune and provided a fresh look at a long-lived storm circling around the north polar region on Uranus.

 A Hubble image of Neptune taken in September 2018 showing the latest storm vortex in the northern hemisphere. Credit: NASA, ESA, and M.H. Wong and A. Hsu (University of California, Berkeley)

The latest images of Neptune from Hubble show a large, dark storm in the planet’s northern hemisphere. It is fourth and latest mysterious dark vortex captured by Hubble since 1993. Prior to this, two other storms were spotted by Voyager 2 in 1989 as it flew by the remote planet. A study led by University of California, Berkeley, undergraduate student Andrew Hsu estimates that the storms appear every four to six years at different latitudes and disappear after about two years.

The current storm was spotted by Hubble in September 2018, and is estimated to be 10,880 km (6,800 mi) across. It is accompanied by white companion “clouds”, similar to those seen with previous vortices. Similar to the pancake-shaped clouds that appear when air is pushed up over mountains on Earth, these while formations are thought to be the result of the vortices perturbing the lower reaches of the atmosphere and diverting it upward, causing gases to freeze into methane ice crystals. The long, thin cloud to the left of the dark spot is a transient feature that is not part of the storm system.

It’s unclear how these storms form, but like Jupiter’s Great Red Spot, the dark vortices swirl in an anti-cyclonic direction. Tracing back through Hubble’s observations of Neptune reveals that the area of the storm saw increased cloud activity from 2016 onwards, suggesting the vortices develop deeper in Neptune’s atmosphere, becoming visible only when their tops reach higher altitudes.

A Hubble image from November 2018 showing the huge white storm in Uranus’ northern hemisphere. The white ring around the planet’s equatorial region matches other features seen on the planet, but its unclear precisely how they form. Credit: NASA, ESA, and M.H. Wong and A. Hsu (University of California, Berkeley)

The snapshot of Uranus, like the image of Neptune, reveals a dominant feature: a vast bright stormy cloud cap across the north pole. It’s believed to be a result of Uranus’ unique rotation.

Unlike every other planet in the solar system, Uranus is tipped over almost onto its side. Because of this, during the planet’s summer the Sun shines almost directly onto the north pole and never sets, both illuminating the north polar region and causing seasonal changes in atmospheric flow that result in the cloudy cap.

Near the edge of the polar storm is a large, compact methane-ice cloud, which is sometimes bright enough to be photographed by amateur astronomers. A narrow cloud band encircles the planet a little north of the equator, the formation of which has also yet to be determined.

The new Neptune and Uranus images are from the Outer Planet Atmospheres Legacy (OPAL) programme, a long-term Hubble project that annually captures global maps of our solar system’s outer planets when they are closest to Earth in their orbits.

OPAL’s key goals are to study long-term seasonal changes, as well as capture comparatively transitory events, such as the appearance of Neptune’s dark spot. Astronomers hope that Hubble’s long-term monitoring of the outer planets will help them unravel what is going on within them that drives their complex weather patterns.

Commercial Crew Test Flight Slip Again

On Wednesday, February 6th, NASA announced that the planned test flights for the new commercial crew transportation systems – the Crew Dragon from SpaceX and the CST100 Starliner from Boeing – have been further delayed.

The initial uncrewed flight of Crew Dragon, previously scheduled for no earlier than February 23rd, will now not take place any earlier than March 2nd. Similarly, the first uncrewed test flight of the CST100 has been pushed back from March to April at the earliest. The crewed test flights for the two vehicles will now not take place any earlier than July 2019 for the Crew Dragon and no sooner than August for the CST100.

SpaceX Crew Dragon (l) and the Boeing CST-100 Starliner: initial flights delayed. Credit: SpaceX / Boeing

No specific technical issues for the delays were given, nor was any mention made of the recent five-week US government shut down. All NASA would say is that the revised dates are to allow for completion of necessary hardware testing, data verification, remaining NASA and provider reviews, as well as training of flight controllers and mission managers.

The uncrewed flight tests are a great dry run for not only our hardware, but for our team to get ready for our crewed flight tests. NASA has been working together with SpaceX and Boeing to make sure we are ready to conduct these test flights and get ready to learn critical information that will further help us to fly our crews safely.

– Kathy Lueders, NASA’s commercial crew programme manager

While the revisions to the dates are not drastic, they have sparked concerns in some quarters that the knock-on impact might leave NASA unable to certify either vehicle before the end of 2019, when the arrangement with Russia to fly US astronauts to the International Space Station aboard Soyuz expires. However, NASA continues to expect that at least one of the vehicles will be ready for operational missions by the end of this year.