Space Sunday: rockets, exoplanets landers and asteroids

Fire in the hole! the Falcon Heavy’s 27 Merlin engines are test-fired on Pad 39A at NASA’s Kennedy Space Centre, January 24th, 2018. Credit: SpaceX

SpaceX faces a busy couple of weeks for the end of January and the start of February 2018. On Tuesday, January 30th, the company is set to launch Luxembourg’s SES-16/GovSat 1 mission on a Falcon 9 rocket from Launch Complex 40 at Canaveral Air Force Station on Florida’s coast. As is frequently the case with SpaceX missions, an attempt will be made to return the booster’s first stage to a safe landing  – this time at sea, aboard the Autonomous Spaceport Drone Ship Of Course I Still Love You in the Atlantic Ocean.

Then, if all goes according to plan, on Tuesday, February 6th, SpaceX will conduct the first launch of the Falcon Heavy booster which should be a spectacular event. As I’ve previously noted in these updates, Falcon Heavy is set – for a time at least – to be the world’s most powerful launch vehicle by a factor of around 2, and capable of lifting up to 54 tonnes to low Earth orbit, and of sending payloads to the Moon or Mars. The core of the rocket comprises three Falcon 9 first stages strapped side-by-side, two of which have previously flown missions.

For its first flight, the Falcon Heavy is set to send an unusual payload into space: a Tesla Roadster owned by Tesla and SpaceX CEO Elon Musk. It’s part of a tradition with SpaceX: mark a maiden flight with an unusual payload; the first launch of a Dragon capsule, for example, featured a giant wheel of cheese. If all goes according to plan, SpaceX hope to recover all three of the core stages by flying them back for touch downs; two of them on land, and one at sea using an Autonomous Spaceport Drone Ship.

The Falcon Heavy is raised to a vertical position on December 28th, 2017 in a launch pad “fit test”. Credit: SpaceX

As part of the preparations for any Falcon launch, SpaceX conduct a static fire test of the rocket’s main engines.For the Falcon Heavy, this took place on January 27th, 2018. These tests have come in for criticism from some quarters as a high-rick operation. However, to date, SpaceX has not suffered a single loss as part of such a test, although in September 2016, a Falcon 9 and its payload were lost while the vehicle was being fuelled in preparation for such a test. For the Falcon 9, the test involves firing the 9 Merlin main engines for between 3 and 7 seconds; with the Falcon Heavy test, and possibly to obtain additional vibration and stress data ahead of the launch, all 27 engines were fired for a total of 12 seconds – almost twice as long as the longest test of a Falcon 9.

Assuming the launch is successful, it will pave the wave for Falcon Heavy being declared operational. The second launch will most likely carried a Saudi Arabian communications satellite into orbit, and the third flight of the Heavy undertake the launch of multiple satellites. All three launches will be watched closely by the US Air Force, who are considering using the Falcon Heavy as a potential launch vehicle alongside the Falcon 9, which was added to the military launch manifest in 2016.

TRAPPIST-1: Further Look At Habitability

Since the confirmation of its discovery in February 2017 (read more here), the 7-exoplanet system of TRAPPIST-1 one has been the subject of much debate as to whether or not anyone of the planets might be habitable – as in, have suitable conditions in which life might arise.

As I’ve previously reported, while some of the seven planets sit within their parent star’s habitable zone where liquid water might exist, there are some negative aspects to any of the Earth-sized worlds harbouring life or having the right conditions for life. In particular, their parent star is a super cool red dwarf with all internal action entirely convective in nature. Such stars tend to have violent outbursts, so all seven planets are likely subject to sufficient irradiation in the X-ray and extreme ultraviolet wavelengths to significantly alter their atmospheres and rendering them unsuitable for life. Further, all seven are tidally locked, meaning they always keep the same face towards their parent star. This will inevitably give rise to extreme conditions, with one side of each world bathed in perpetual daylight and the other in perpetual, freezing darkness, resulting in atmospheric convection currents moving air and weather systems / storms between the two.

Artist’s concept showing what each of the TRAPPIST-1 planets may look like. A new study suggests TRAPPIST-1d and 1e might be the most potentially habitable. Credit: NASA

However, on the positive side, TRAPPIST-1 is sufficiently small and cool that, despite their proximity to it, the sunward faces of the planets won’t be as super-heated as might otherwise be the case. This also means that the extremes of temperature between the lit and dark sides of the planets aren’t so broad, reducing the severity of any storms some of them might experience. Now a team of researchers have identified the more likely planets within the seven which might have conditions conducive for life.

This involved certain assumptions being made, such as all the planets being composed of water ice, rock, and iron, and – given some of the data concerning the planets, such as their radii and masses, are not well-known – a range of computer models having to be built.

In putting everything together, the team concluded that TRAPPIST -1d and TRAPPIST-1e might prove to be the most habitable, with TRAPPIST 1d potentially being covered by a global ocean of water. The study also suggests that TRAPPIST-1b and 1c have have partially molten rock mantles, and are likely to be heavily volcanic in nature.

In publishing their work, the team are reasonably confident of their findings, but note that improved estimates of the masses of each planet can help determine whether each of the planets has a significant amount of water, allowing better overall estimates of their compositions to be made.

Lunar X Prize to Go Unclaimed

The foundation running the Google Lunar X Prize announced Jan. 23 that the US $20 million grand prize for a commercial lunar lander will expire at the end of March without a winner.

The X Prize Foundation said none of its five finalist teams would be able to complete the task of soft landing a vehicle on the Moon and have it – or a rover it is carrying – travel a minimum distance of 500 metres and return high-resolution images and video to Earth, before March 31st, 2018. They were therefore – with Google’s approval – ending the challenge.

A Moon Express MX lander. Credit: Moon Express

In all, some US $30 million was put up in prize money for competition, which was established in September 2007. At the time, the US $20 million grand prize for the first team to complete the challenge was set to decrease to $15 million if not won by the end of 2012, and expire if not claimed by the end of 2014. However, technical and financial  issues faced by the entrants meant the deadline for completing the challenge was extended several times. In 2017, things appeared to settle down when five finalists were selected to complete the challenge.

This required the five teams – Moon Express, SpaceIL, Synergy Moon, TeamIndus and Team Hakuto to launch their missions to the lunar surface by the end of 2017. As all five continued to face technical or financial problems, the deadline was given a final extension – to March 31st 2018, with the Foundation indicating no more extensions would be given. As none of the finalist was able to confirm they would be in a position to launch prior to the deadline, the decision was made to end the current competition.

Even so, in announcing the decision, X Prize Foundation founder Peter Diamandis and Executive Chairman Marcus Shingles suggested the competition might be able to continue, possibly with s new sponsor and prize purse, of even as a non-cash prize competition, tracking the entrants – all of whom have indicated they will continue in their attempts to reach the Moon.

The Space IL Lunar X Prize entrant. Credit: Space IL

“Disappointment is certainly there,” said Naveen Jain, chairman of Moon Express, before emphasising the X Prize was not a major goal for the company, which is focused on mining the Moon for its natural resources. “From our perspective, it doesn’t really matter that much, he said. “We started Moon Express fundamentally because it’s a good business, and that does not change.” Instead, the company will continue development of its MX series of lunar landers, but with relaxed schedules given the lack of a prize deadline.

TeamIndus, the Indian finalist, has expressed similar sentiments, and are determined to see through an agreement with Team Hakuto of Japan to fly their rover on the Indian lander. The Israeli SpaceIL Team is still trying to raise funding for their mission, but have stated a desire to continue efforts, acknowledging they can now pursue the goal of landing on the Moon at their own pace.  The last finalist, the international Synergy Moon, has taken the most aggressive line on the ending of the competition, stating they will be launching their mission before the end of 2018, but declined to give specifics.

Asteroid 2002 AJ129 Will Pass Earth Safely on February 4th

The more sensationalist tabloids and YouTube channels have been full of excitement over the “risk” that Earth would be struck by an asteroid at the start of February – with some pointing to NASA’s “silence” on the matter as some kind of “proof” the Earth was in danger.

While it true  a quite substantial asteroid – 2002 AJ129, between 500 and 1,200 metres across, and classified as an intermediate-sized near-Earth asteroid – will pass us on February 4th, 2018, it poses no threat. Rather, when it crosses Earth orbit at 21:30 UTC, it will do so at some 4.2 million km (2.6 million miles) from Earth, travelling at a velocity of 34 km per second (76,000 mph).  This is a higher than average velocity for a near-Earth asteroid, due to 2002 AJ129 passing within 18 million km (11 million mi) from the Sun in it’s 588 day orbit.

Artist’s impression of 2002 AJ29

2002 AJ129 was discovered on Jan. 15, 2002, by the former NASA-sponsored Near Earth Asteroid Tracking project at the Maui Space Surveillance Site, Hawaii. It has an observation arc of over 14 years, making it one of the most well-known objects under observation from Earth. This means that astronomers are able to predict the distances at which the asteroid will pass the Earth with reasonable accuracy. The February 4th pass, for example, has an accuracy of +/- 200 km – meaning Earth was never in any danger.

The further ahead astronomers attempt to predict the asteroid’s passages past the Earth, the less accurate they become – but not enough for the asteroid to become a genuine threat. For example the close approach of February 19th, 2196, the degree of accuracy with which the asteroid’s passage can be predicted is +/- 2.4 million km. But given the average distance the asteroid will be from Earth at the time will be some 36 million km (22.5 million mi), even the margin of error in the prediction doesn’t bring the asteroid dangerously close to Earth.

The reason tabloids and video posters may have become all excited is because while it poses no threat, 2002 AJ129 is classified a potentially hazardous asteroid (PHA). However, this designation does not mean there is a near-term threat of an impact; rather it is term derived merely as a result an object’s size (absolute magnitude) and its Earth minimum orbit intersection distance.

Commenting on the asteroid’s passage around the Sun, Paul Chodas, manager of NASA’s Centre for Near-Earth Object Studies at the Jet Propulsion Laboratory, California, said,”We have been tracking this asteroid for over 14 years and know its orbit very accurately. Our calculations indicate that asteroid 2002 AJ129 has no chance – zero – of colliding with Earth on February 4th or any time over the next 100 years.”

 

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