Category: Space Sunday

Spirit, one of NASA’s two solar-powered Mars Exploration Rover (MER) missions, may have ceased communications with Earth on March 22nd, 2010 and the mission declared over on May 24th, 2011, but its science legacy lives on.

Originally designed with a 90-day primary mission duration, Spirit massively exceeded this, ranging across Mars for a distance of 7.73 kilometres (4.8 mi) over 1,944 days of mobile operations before becoming bogged down in a sand trap on May 1st, 2009, almost 5.5 years after it had arrived on Mars, after which it operated as a stationary research programme for a further 751 days.

During its mobile period, Spirit explored a small rocky plateau dubbed “Home Plate” in 2007 / 2008. Whilst exploring the rock, the rover imaged several peculiar small rock formations resembling cauliflower or coral.  Analysis by the rover’s Mini-Thermal Emission Spectrometer (Mini-TES) revealed the formations to be almost pure silica (SiO2), a mineral associated with volcanic environments.

Silica is formed when water (rain or snow) seeps underground and comes into contact with rocks heated from below by magma. Itself super-heated by the rocks, the water is vaporised and rises back through the ground, dissolving silica and other minerals as it does so, which it deposits around the vents or fumaroles it uses to escape back into the atmosphere.

Warm, rich in silica and minerals, on Earth these fumaroles and vents become havens for bacterial life which is known for creating curious bulbous and branching shapes in silica formations here on Earth which are strikingly similar to those imaged by Spirit. Such is the similarity, that planetary geologist Steven Ruff and geology professor Jack Farmer, both from Arizona State University, have been carrying out detailed studies in the high Atacama Desert, regarded as the most arid non-polar region on Earth, harbouring conditions thought to be very similar to those of ancient Mars.

In particular, they have been investigating the remote geyser fields of El Tatio, some 4.3 km  above mean sea level in an environment which has much in common with the Gusev Crater region of Mars, where “Home Plate” resides. This includes being exposed to high levels of ultraviolet light from the sun and extreme temperatures.  Their investigations revealed forms they call “micro-digitate silica structures” which are both remarkably similar to the formations on Mars, and to those found around fumaroles and vents at lower altitudes here on Earth which are formed by bacteria.

While the pair have yet to come up with definitive evidence that the El Tatio formations are the result of microbial activity, they believe the objects may be “micro-stromatolites”.  Nornally of a much larger size, stromatolites are formed by bacteria “cementing” mineral grains together to form a thin layer. Over time, these layers accumulate one over the last, forming a laminar mound or rock. The oldest stromatolites on Earth are estimated to be some 3.5 billion years old, a time when both Earth an Mars may have shared much closer atmospheric and geological similarities. So, if the formations found at El Tatio do prove to be the result of bacterial activity, then it offers a hypothesis that the formations on Mars may also have been the result of bacterial activity.

Dream Chaser: the Dream is Alive

In January, I wrote about NASA’s surprise decision to award an extended contract for uncrewed resupply missions to  the International Space Station to both of the existing contract holders, SpaceX and Orbital ATK, and to Sierra Nevada Corporation, who will use an uncrewed variant of their Dream Chaser space plane.  At the time I wrote that update, reader Devin  Vaughn indicated an interest in learning more about Dream Chaser, which has an interesting heritage.

As I noted at the time, the vehicle had been one of four private sector contenders to fulfil the role of “space taxi”, ferrying up to 6 at a time from US soil to the ISS. The idea being that by spinning-out the ISS crewed flights to the private sector (with financial support from NASA), the US agency could focus its manned space flight development programme solely on the Orion / SLS programme, which is intended to form the nucleus of US (and possibly international) crewed mission ventures well beyond Earth orbit.

Dream Chaser ultimately wasn’t selected for the crewed mission contract – which caused some friction between Sierra Nevada Corporation and NASA when it was announced in 2014 – but the US space agency continued to work with SNC to help develop the vehicle,  with the Dream Chaser Cargo variant being the result – although SNC has not given up on developed the crewed version of the vehicle.

Dream Chaser Cargo is designed to fly up to 5 tonnes of cargo to / from orbit. This can be both pressurised and unpressurised material, and the vehicle includes the ability for unpressurised cargo to be directly transferred from its cargo module to the exterior of the space station should this be required. As with the original crewed variant, Dream Chaser Cargo will launch atop a rocket, but return to earth to make a conventional runway landing, the latter greatly speeding up the transfer of returned cargo (e.g. science experiments material, etc.) from the vehicle to its intended destination.

Continue reading “Space Sunday: Martian “coral”, Planet Nine and Dream Chasers” →

This week marked a sombre period in the annals of NASA’s history. In a period of just 7 days – albeit spread across 50 years – America lost 17 astronauts in just three space flight related tragedies. Every year, the US space agency marks this loss of life – the results of the Apollo 1, Challenger and Columbia accidents – with a special Day of Remembrance on the 27th January. This year’s event was particularly poignant in that 2016 marks the 30th anniversary of the Challenger disaster.

It was on January 27th, 1967, that NASA suffered the first of these tragedies when, during a pre-launch rehearsal of what was intended to be the first manned flight of the Apollo Command and Service modules, a fire broke out inside the Command Module as the vehicle sat on the pad of Cape Kennedy Air Force Station Launch Complex 34. A combination of a pure oxygen atmosphere at a high internal PSI, and highly flammable materials used in the vehicle’s interior construction resulted in the deaths of Command Pilot Virgil I. “Gus” Grissom, Senior Pilot Edward H. White II, and Pilot Roger B. Chaffee in just 16 seconds.

Nineteen years later, on January 28th, 1986, NASA suffered its largest loss of life in a space mission up until that point in time. It occurred when Space Launch System mission 51L, the 25th flight in the space shuttle programme and the 10th flight of the shuttle orbiter vehicle Challenger – regarded as the veteran of the fleet, having flown more orbital missions than the other three orbiter vehicles at that time – exploded 73 seconds after launch, resulting in the loss of all seven crew.

Tragedy struck the space shuttle programme again on February 1st, 2003, when the space shuttle Columbia broke-up following re-entry into the Earth’s atmosphere at the end of mission STS-107, killing all seven crew. On board were Commander Rick Husband, Pilot William McCool, Payload Commander Michael Anderson, Mission Specialists Laurel Blair Salton Clark, Kalpana Chawla, David M. Brown, and Payload Specialist  Ilan Ramon, a colonel in the Israeli Air Force and the first Israeli astronaut.

There have of course been other lives lost within the fraternity of astronauts and cosmonauts over the decades. However, these three tragedies perhaps stand larger than others because NASA has always undertaken its missions in the full glare of the public and media spotlight. Apollo 1, for example, was the headline mission for America meeting President Kennedy’s requirement for “landing a man on the Moon and returning him safely to the Earth” before the end of the decade. Similarly, STS-51L, the Challenger mission, had been specifically engineered to be in the public eye, featuring as it did the first teacher in space, Sharon Christa McAuliffe.

McAuliffe had been selected from more than 11,000 applicants to participate in NASA’s Teacher in Space Project, initiated by US Present Ronald Reagan and intended by NASA to rejuvenate public interest in the space programme, which has been declining steadily since the first space shuttle flight in 1981. The gamble paid off and McAuliffe, became a media sensation, attracting world-wide public interest in STS-51L; so much so that it has been estimated that around 17% of Americans watched Challenger’s lift-off live on television as a direct result of McAuliffe’s presence on the mission, and that around 85% heard about the disaster within an hour of it occurring (and if that doesn’t sound unusual, remember 1986 was well before the Internet and media revolution what has placed information and news at our fingertips wherever we are).

It could be argued – particularly with regards to Challenger, and also with Apollo 1, that the disaster could have been avoided. Warnings about the precise type of failure which caused the loss of Challenger date back as far as 1971, which tests carried out in 1977 revealing the risk of what because known as an O-ring failure being inherent in the design of the shuttle’s solid rocket boosters.

Things are less clear in the case of the Columbia tragedy; while it has been suggested that a rescue mission might have been mounted using the shuttle orbiter Atlantis, which was being prepared for a mission due to lift-off at the start of March, 2003. However, in order to get the vehicle flight ready for a launch ahead of the February 15th deadline (the point at which lithium hydroxide, a critical part of the systems used to remove carbon dioxide from the air in a space vehicle, would run out aboard Columbia), was itself fraught with risks.

But whether they could be avoided or not, these three disasters remind us that the cost of becoming a space faring civilisation – something which could be vital to our survival – is not without risk. Which is why I’ll close this part of Space Sunday with the words of Francis R. Scobee, the Commander of STS-51L, written shortly before his death aboard the Challenger:

Continue reading “Space Sunday: day of remembrance, seeing Mars and flying over Ceres” →