Tag: Spaceflight

Throughout human history – and outside of flights of fancy – the Moon has always been thought of as an airless ball of rock, tidally locked to Earth so that it shows the same, almost never-changing face to us in the night sky. But it may not always have been so.

In recent years, our perceptions of the Moon have been changing as a result of a number of studies and missions. In 2009, for example, India’s first lunar mission, Chandrayaan I, produced a detailed chemical and mineralogical map of the lunar surface, revealing the presence of water molecules in the lunar “soil”. In that same year, NASA launched a pair of missions to the Moon, the Lunar Reconnaissance Orbiter (LRO) mission and the Lunar Crater Observation and Sensing Satellite (LCROSS).

LCROSS was a small satellite designed to follow the upper stage of the rocket used to launch it and LRO to the Moon and analyse the plume of debris created by the impact of the upper stage with Cabeus crater in the Moon’s south polar region. The impact came with a kinetic energy equivalent of an explosion created using 2 tons of TNT, and LCROSS recorded strong evidence of water within the resultant impact plume.

For its part, LRO entered lunar orbit to commence a comprehensive campaign of mapping, imaging and probing the Moon’s surface and environment. In doing so, it further confirmed the presence of abundant concentrations of water in the lunar south polar regions. At the same time and LRO has been studying the Moon, an ongoing analysis of the rock samples brought back by the Apollo astronauts has revealed strong evidence for a large amount of water being present in the lunar mantle – possibly as much as is present in Earth’s upper mantle.

These results and findings have given rise to the idea that very early on in the Moon’s history conditions could have been very different to how it is now. In the immediate period following the Moon’s creation (roughly four billion years ago), there are a period when it was very volcanically active (about 3.8-3.5 billion years ago), releasing considerable amounts of superheated volatile gasses, including water vapour, from its interior. This outgassing could have given rise to an atmosphere around the Moon dense enough to support that water vapour condensing out into liquid on the surface which could have conceivably lasted for several million years whilst the atmosphere remained dense enough to support it, before it either (largely) evaporated or retreated underground to eventually freeze.

In their new study, published in July 2018, Dirk Schulze-Makuch, a professor of astrophysics at Washington State University, USA, and Ian A. Crawford, a professor of planetary science and astrobiology at Birkbeck College, University of London, UK, review the evidence for liquid water to have been present on the Moon and examine the potential for it to have been life-bearing. In particular, they note that when all is said and done, if the early conditions on the Moon did give rise to a dense atmosphere and a water-bearing surface, then the conditions there wouldn’t have been that different to those being experienced on Earth when life here was starting up, and would have occurred in the same time frame.

It looks very much like the Moon was habitable at this time. There could have actually been microbes thriving in water pools on the Moon until the surface became dry and dead.

Dirk Schulze-Makuch, co-author of Was There an Early Habitability Window for Earth’s Moon?,
quoted in Astrobiology Magazine

So does that mean life, however transient, got a start on the Moon? Possibly; however, some have suggested rather than giving rise to life directly, the conditions on that early Moon might have been ideal for life from Earth to gain a toe-hold.

As noted, the period when the Moon may have had its dense atmosphere coincided with life starting on Earth in a period referred to as the Late Heavy Bombardment, (4.1 and 3.8 to 3.5 billion years ago). During that time, bacteria such as cyanobacteria were believed to be already present on Earth, even as it was being bombarded by frequent giant meteorite impacts (hence the period’s name). So the suggestion is that this bombardment could have thrown chunks of bacteria-laden rock into space, where they were “swept up” by the Moon, transferring the bacteria to its surface, where it might have taken hold.

It’s unlikely that if it go started, life on the Moon got very far; within a few million years after the end of the Moon’s volcanic period the atmosphere would have been lost, and conditions would have become far too harsh for life to endure. However, in noting this, Crawford and Schulze-Makuch use their study as a call for a more robust study on the potential ancient habitability of the Moon, including a hunt for possible biomarkers.

Such an endeavour would likely be focused on the lunar south polar regions, simply because of the potential abundance of subsurface frozen water there. And as it is, NASA, India and China are already committed to studying the region in great detail. NASA will initially do so from orbit, while the Indian Chandrayaan-2 mission will attempt to place a lander and rover close to the Moon’s south pole in 2019. Also in 2019, China will send its  Chang’e 5 mission to the Moon’s north polar regions to gather and return around 2 kg of rock samples for detailed analysis on Earth.

Continue reading “Space Sunday: questions of life, and the “Commercial Nine”” →

Friday, July 27th marked the longest lunar eclipse of the 21st century, which was visible from southern Africa, Australia, and Madagascar, Europe, South Asia and South America. Although many of us in the UK largely (and typically!) missed out, as the summer heat wave gave way to rain and clouds, a bit of a double blow, given we were just outside the reach of totality.

For about half the world, the Moon was partly or fully in Earth’s shadow from 17:14 to 23:28 GMT; six hours and 14 minutes in all, with the period of totality – when the Moon lies entirely within the Earth’s shadow, and so is at its darkest – lasting from 19:30 to 21:13 GMT.

In a special treat, Mars, which is currently at opposition, sitting on the same side of the Sun as Earth, and thus at its closest to Earth (roughly 92 million km /  57 million mi), was visible just below the eclipsed Moon, appearing as a bright “star”. Those blessed with clear skies also had the treat of Saturn, Jupiter and Venus being visible in the sky as well.

The reason the eclipse lasted so long was that the alignment between Sun, Earth and Moon meant that the Moon was passing right across the middle of the disc of shadow cast by the the Earth. This also meant this eclipse created a particularly strong blood Moon. This is a phenomena caused by the lensing effect of the Earth’s atmosphere scatters blue light from the Sun outwards, whilst refracting red light inwards, so the Moon appears rusted as  seen from Earth.

Virgin Galactic Reach Mesosphere for the 1st Time

VSS Unity took to the skies on July 26th, 2018, and reached its highest altitude yet: 52,000 metres (170,800 ft), the highest any Virgin Galactic vehicle has thus far reached.

VMS (Virgin Mother Ship) Eve, the WhiteKnightTwo carrier aircraft, took off from the Mojave Spaceport at 15:45 GMT and climbed to an altitude of 14,000 metres (46,500 ft), prior to releasing Unity, which dropped clear prior to its single rocket motor being ignited. The engine burned for some 42 seconds, powering the vehicle into a near vertical ascent and a speed that reached Mach 2.47.

This was enough to propel Unity on a parabolic flight that topped-out at 52,000 m, inside the mesosphere, which spans heights from approximately 10 km (33,000 ft; 6.2 mi) to 100 km (62 mi; 330,000 ft), representing the heights to which Virgin Galactic flights will typically carry fare-paying passengers so they can enjoy around 5 minutes of weightlessness.

It was a thrill from start to finish. Unity’s rocket motor performed magnificently again, and Sooch [co-pilot Mike Masucci] pulled off a smooth landing. This was a new altitude record for both of us in the cockpit, not to mention our mannequin in the back, and the views of Earth from the black sky were magnificent.

– Virgin Galactic’s chief pilot, Dave Mackay

The mesosphere is sometimes referred to the “ignorosphere”, as it sits above the range of instrument carrying balloons, but well below the height from which it can be studied from space, and so remains one of the least-studied parts of the atmosphere. As well as carrying passengers aboard their vehicles, Virgin Galactic plan to change this by also flying experiments up to the mesosphere that might be used to probe it.

As with previous flights, today’s test flight was designed in part to gather additional data about conditions in the cabin during flight, but it also marks a significant step closer to the company starting commercial tourist flights, which are currently earmarked to commence in 2019, or possibly the end of 2018. Before that, however, the company will make at least one flight  with Unity’s motor fuelled for a full duration burn of 60 seconds. When that might be, and whether it might follow  directly on from this flight (which represented an 11 second longer engine burn than previous flights) or be worked up to, has yet to be stated.

When operational, VSS Unity will be joined by at least two more SpaceShipTwo vehicles, and – at some point in the next couple of years – an additional WhiteKnightTwo carrier vehicle, given the company are looking to operate flights out of Italy as well.

Continue reading “Space Sunday: an eclipse, a space ship, lasers and a birthday” →

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” →