Category: Space Sunday

The first SpaceX Crew Dragon (aka Dragon 2) vehicle destined to fly in space has arrived in Florida ahead of its launch, due in August 2018. The capsule is intended to be part of an uncrewed first flight to test the vehicle’s flight test systems.

Prior its transfer to Kennedy Space Centre (KSC), the capsule and service module were the subject of extensive thermal vacuum chamber tests at NASA’s Plum Brook Station in Ohio. The world’s only facility capable of testing full-scale upper-stage launch vehicles and rocket engines under simulated high-altitude conditions, the chamber is a vital part of pre-launch testing – although by the date of the capsule’s arrival at KSC, the results of the Ohio testing had not been made public.

No official date for the first Crew Dragon flight has been released, but SpaceX are pushing ahead with work to prepare the vehicle for launch, in anticipation of the flight being given the green light for August. The test flight should see the uncrewed test vehicle fly to the International Space Station (ISS), with a follow-up 14-day crewed test flight due to take place in late 2018 / early 2019.

The arrival of the Crew Dragon test article at KSC came at the same time as a further US government report raised concerns about both SpaceX and Boeing – the other company contracted to make crewed flights to / from the ISS using their CST-100 Starliner capsule – being able to meet the current schedule for commencing formal operations.

A July 11th, 2018, report from the independent Government Accountability Office (GAO) points out that if any significant issues arise with either / both vehicles prior to their formal certification, it could see one or other or both companies being unable to commence active crew launches within the anticipated time frames specified by NASA. Were this to be the case, America would effectively be without the means to send astronauts to the Space Station, as the current contract to fly US crew aboard Russian Soyuz vehicles expires in November 2019.

Under the original schedule, the Boeing CST-100 was to have been certified for crew operations in January 2019, and the Crew Dragon in February 2019. However, both these dates were recently revised: the CST-100 certification slipping to December 2019 and Crew Dragon’s to February 2020.

With crew rotations to the ISS lasting 6 months, this slippage – which moved the first official crewed flights of both CST-100 and Crew Dragon to several months after the Soyuz contract ends – were not seen as a significant issue. However, the GAO report warns that certification of both vehicles could slip to around August 2020 should difficulties with either / both vehicles be encountered as a result of the test flights (or other reasons). This would potentially see a nine-month gap open between the last of the planned US Soyuz flights and a commencement of CST-100 / Crew Dragon flights, more than the span of a crew rotation, with no contingency currently in place to allow continued US access to the ISS until either of the new vehicles is ready to fly.

A “Temperate” Exoplanet?

Ross 128 is a red dwarf star just 11 light-years away from our Sun that over the years has been a source of interest for astronomers. First catalogued in 1926, the star is too faint to be seen with the naked eye, but is classified an old disk star with a low abundance of elements other than hydrogen and helium. Like most red dwarf stars, Ross 128 is given to violent flare activity, although its extreme age makes such events a lot less frequent than “younger” red dwarfs.

In mid-2017, Ross 128 caused something of a stir when a mysterious burst of signals was recorded apparently coming from its general vicinity. Dubbed the “Weird!” signals, the series of unusual “transmissions” were received by the  Arecibo radio telescope, Puerto Rico on May 12th/13th, 2017.

At the time, the signals caused a lot of excitement and talk of “aliens” being involved – although no planets had actually been detected around Ross 128. As I reported in July 2017, after further study, it was determined that the most likely explanation for the signals was that they’d been accidentally picked up from satellites occupying the same part of the sky as Ross 128 at the time Aricebo happened to be listening; all attempts to re-acquire them by numerous radio telescoped failed to do so.

While there is no reason to change the view that the odd signals of May 2017 were from local satellites rather than originating with Ross 128, in November 2017 it was confirmed the star does in fact have a planet orbiting it.

Referred to as Ross 128 b, the planet was first detected in July 2017 by a team operating the High Accuracy Radial velocity Planet Searcher (HARPS) instrument at the La Silla Observatory in Chile. However, it was not until November of 2017 that the astronomers were able to confirm that had located the planet.  Since then, the planet has been the subject of indirect scrutiny to try to better determine its characteristics, and the results are interesting.

The HARPS data initially suggested the planet to be roughly around the size of Earth and orbiting in the star’s habitable zone. However, further characterisation of the planet – including whether or not it has an atmosphere – has been hampered by the fact that its orbit around its parent star means it doesn’t actually transit between Ross 128 and Earth.

As this presents a barrier to analysing the planet directly by the effect it and its atmosphere (if it has one) has on light coming from its parent star, astronomers instead turned to studying Ross 128 itself in their attempts to better understand the potential nature of Ross 128 b.  In particular, a team led by Diogo Souto of Brazil’s Observatório Nacional used Sloan Digital Sky Survey‘s APOGEE spectroscopic instrument to measure the star’s near-infrared light to derive abundances of carbon, oxygen, magnesium, aluminium, potassium, calcium, titanium, and iron.

Continue reading “Space Sunday: of rockets and planets” →

China may be preparing to de-orbit its Tiangong-2 orbital laboratory, possibly to avoid a situation similar to that relating to the so-called “uncontrolled” re-entry of their Tiangong-1 facility, which re-entered the Earth’s atmosphere and broke-up / burnt-up in April 2018.

Orbital information published by the U.S. Strategic Command’s Joint Force Space Component Command, through the Joint Space Operations Centre, indicates that Tiangong-2 has moved from an altitude of around 380 by 386 km down to 292 by 297 km.

No official announcement regarding the status of the Tiangong-2 space lab has been made by the China Manned Space Engineering Office (CMSE), however, China has made no secret of its plans to establish a permanent orbital presence over the Earth in the 2020s – and that to do so, they would discontinue operations with both Tiangong-1 and Tiangong-2. and de-orbit both.

Measuring 10.4 metres in length and some 3.3 metres in maximum diameter, Tiangong-2 weighs 8.6 metric tonnes – making it the same overall size and weight as Tiangong-1, launched in 2011. The re-entry of that unit came after a series of alarmist headlines claiming it would “crash” to Earth after it was reported the Chinese only had partial control over it. Because of that tabloid farrago, some have speculated the alteration in Tiangong-2’s orbit is to allow China to retain full control over the facility, including when it re-enters the atmosphere.

Launched in September 2016, Tiangong-2 hosted a single crewed visit that same year, which lasted 30 days. In 2017 served as a test-bed for verifying on-orbit automated docking and refuelling capabilities  – two aspects of operations vital to the Chinese ambitions of developing their large-scale space station – using the Tianzhou-1 cargo spacecraft.

Tiangong-2 carried a range of science payloads, including POLAR, a gamma-ray burst detector developed by an international collaboration including Swiss, Chinese and Polish institutes. According to principal investigator Nicolas Produit, this astro-particle experiment collected excellent data during six months of operations, with science results to be published shortly. It is the kind of international collaborative effort China would like to develop with its new station.

China is aiming to launch the first module of the space station proper, named Tianhe, around 2020. This mission first requires the nominal return-to-flight of the heavy lift Long March 5 launch vehicle, which suffered a launch failure in July 2017. When completed, the space station will mass between 60 and 100 metric tonnes, including two experiment modules due for launch in 2022. It will be capable of hosting three astronauts in rotations of up to six months at a time. A further element of the station will be a free-flying Hubble-class space telescope capable of docking with the station to receive propellants and undergo maintenance and repairs.

More on Ceres and the Building Blocks of Life

In February 2017, I wrote about the discovery of the basic building blocks of life on Ceres, which has been the subject of the joint NASA / ESA Dawn mission since March 2015.

The discovery of aliphatic compounds on the surface of Ceres was made by an international team of scientists who had been reviewing data from the Visible and Infra-red Mapping Spectrometer (VIMS) aboard the spacecraft. Now, a new study conducted by a team of researchers from Brown University suggests that these patches contain more organic material than previously thought.

Aliphatics are a type of compound where carbon atoms form open chains that are commonly bound with oxygen, nitrogen, sulphur and chlorine – all of which are necessary for the evolution of life. This doesn’t actually mean that Ceres supports life, because these molecules can also arise from non-biological processes. Nevertheless, the presence of these compounds does raise the questions.

The team behind original discovery of the aliphatics, found within a 1000 km² region around of the Ernutet crater, concluded that between 6 and 10% of the spectral signature detected on Ceres could be explained by organic matter. As hydrothermal activity had been detected on Ceres, the researchers hypothesised that the molecules were endogenous in origin – that is, they came from inside the protoplanet. Given that ammonia-bearing hydrated minerals, water ice, carbonates, and salts have also been detected on Ceres, there is the suggestion that it may have an interior environment that can support prebiotic chemistry.

However, rather than relying on Earth rocks on which to base their work and findings, the team from Brown University used carbonaceous chondrite meteors, which have been shown to contain organic material that is slightly different from what we are familiar with here on Earth. As a result, they determined that the organics found on Ceres were distinct from their terrestrial counterparts – and the up to 40 to 50% of the spectral signal we see on Ceres is explained by organics – far more than originally estimated.

If this latter estimate is correct, it raises the question about where it came from – 40% is a lot for the compound to be entirely endogenous in origin. Rather, the high concentrations seem to be more consistent with being deposited by a comet impact.

Given that the asteroid belt is composed of material left over from the formation of the Solar System,  determining where these organics came from could shed light on how organic molecules were distributed throughout the Solar System early in its history, and the role this distribution may have played in the development of life here in Earth.

If, however, the compound deposits are endogenous in origin, there is still the question of what mechanisms were / are in play to result in such high concentrations emerged in Ceres’ northern hemisphere, and then preserve them in these locations. This is a question unlikely to be answered without follow-up missions able to obtain and analyse samples gathered from the surface of the protoplanet.

Continue reading “Space Sunday: stations, Ceres, doubts and rockets” →