Space Sunday: rockets, red spots, fireballs and spaceplanes

SpaceX's plan to start down the road to their first human mission to Mars with their 2018 automated mission to the Red Planet -which NASA suggest will cost the company around US $320 million

SpaceX’s plan to start down the road to their first human mission to Mars with their 2018 automated mission to the Red Planet – which NASA suggests will cost the company around US $320 million

NASA has indicated that the SpaceX Red Dragon mission to Mars, which the company plans to carry out in 2018, will likely cost around US $320 million for SpaceX to mount, ad NASA itself will spend around US $32 million over four years in indirect support of the mission.

The Red Dragon mission, first announced in April 2016, will be financed entirely by SpaceX; NASA’s costs will be related to providing technical and logistical support – such as using its Deep Space Tracking Network for communications with the vehicle.

If all goes according to plan, the Red Dragon mission could be launched as early as May 2018. It is the crucial first step along the road towards the company’s ambitions to land a human crew on Mars by the end of the 2020s. If successful, it could potentially be followed by at least three further uncrewed Red Dragon flights in 2020/22, prior to the company commencing work on building-up matériel on Mars in preparation for a crewed mission.

A SpaceX / NASA infographic outlining the 2018 mission

A SpaceX / NASA infographic outlining the 2018 mission. Credit: NASA / SpaceX

Red Dragon is the name of an uncrewed variant of the SpaceX Dragon 2 vehicle, which will enter service in 2018 ferrying astronauts to / from the International Space Station. Intrinsic to the mission is the plan to conduct a propulsive landing on Mars using the craft’s SuperDraco Descent Landing capability. This is vital on two counts.

For SpaceX, a crewed variant of the Red Dragon will likely be the Mars descent / ascent vehicle during a human mission to the planet. So understanding how it operates in the Martian atmosphere is a vital part of preparing to land a crew on the planet. NASA is similarly interested in learning how well retropropulsion works in slowing a vehicle to subsonic speeds in the Martian atmosphere, as it now looks likely they will use the same approach for their human missions to Mars, which may occur in the 2030s. Gaining the data from the SpaceX missions means that NASA doesn’t have to fly its own proof-of-concept missions all the way to Mars.

A Dragon 2 text article test-fires its eight SuperDraco engines during a hover test in 2014

Whether or not Red Dragon will fly in 2018 is still a matter of debate. SpaceX has some significant commitments and obligations on which to focus: commercial Falcon launches, resupply missions to the ISS, the start of crewed flights to the ISS, introducing the Falcon 9 into its flight operations, etc. These all tend to suggest that the development of the Red Dragon capsule, which will require some significant modifications when compared to the Dragon 2, will be subject to the company’s existing commitments taking priority over it.

In the meantime, the company plans to release more information on the overall Mars strategy, up to and including their human mission, in September.

Jupiter’s Great Red Spot: Atmospheric Heating for a Giant

As the Juno space vehicle reached the farthest point from Jupiter in its first orbit around the gas giant and begins a 23-day “fall” back towards the planet, scientists on Earth may have unlocked the secret of why Jupiter’s upper atmosphere is so warm.

The Eye of Jupiter: a CGI recreation of the Great Red Spot based on observations from the Voyager spacecraft and Hubble Space Telescope, and as used in the television series Cosmos: A Spacetime Odyssey. Credit: 21st Century Fox.

The Eye of Jupiter: a CGI recreation of the Great Red Spot based on observations from the Voyager spacecraft and Hubble Space Telescope, and as used in the television series Cosmos: A Spacetime Odyssey. Credit: 21st Century Fox.

Here on Earth, the atmosphere is heated by the Sun. However, despite being five times further from the Sun than Earth, the upper reaches of the Jovian atmosphere share similar average temperatures to our own when they should in fact be a lot colder. Many theories have been put forward as to why this is the case, but now a team from Boston University, Massachusetts,  believe they’ve found the answer: the heating of Jupiter’s upper atmosphere is the combined result of the Great Red Spot (GRS) and Jupiter’s aurorae.

The Great Red Spot is one of the marvels of our solar system. Discovered within years of Galileo’s introduction of telescopic astronomy in the 17th Century, it is a swirling pattern of red-coloured gases thought to be a hurricane-like storm raging down through the centuries in the Jovian atmosphere. Roughly 3 Earth diameters across, its winds take six days to complete one spin around its centre, driven in part by Jupiter’s own high-speed spinning about its own axis, completing one revolution every ten hours.

Jupiter's Great Red Spot, 3 times the size of Earth, imaged by Voyager 2 in 1980. Credit: NASA

Jupiter’s Great Red Spot imaged by Voyager 2 in 1980. Credit: NASA

Now, infra-red observations of the upper Jovian atmosphere by the Boston University researchers reveal that the GRS is generating a huge blanket of heat in the tenuous upper reaches of the Jovian atmosphere, about 800 km (500 mi) above the cloud tops, and this heat is being dissipated across the upper atmosphere as a result of Jupiter’s fast rotation.

The cause of the heat is believed to be due to the turbulence within the GRS generating both atmospheric gravity waves (not to be confused with gravity waves) and acoustic waves. These both operate somewhat differently to one another, but their combined result is to generate heat, creating a transfer mechanism between the lower and upper reaches of the planet’s atmosphere.

Turbulence in the GRS gives rise to acoustic waves and atmospheric gravity waves which rise up into the upper reachs of Jupiters atmosphere, where they are compressed, generating a large pocket of heat which radiates outwards, significantly warmly the atmosphere some 80-0 km (500 mi) above the main cloud tops

Turbulence in the GRS gives rise to acoustic waves and atmospheric gravity waves which rise up into the upper reaches of Jupiter’s atmosphere, where they are compressed, generating a large pocket of heat which radiates outwards, significantly warmly the atmosphere some 80-0 km (500 mi) above the main cloud tops

This is the first time such a mechanism for heat transfer between lower and upper atmospheres around a planets a long way from their parent star has been practically demonstrated. If the theory is correct, it could explain why the other gas giants of the solar system have upper atmospheres which are considerable warmer than should be the case.

At the same time, the IR studies carried out by the team show that the massive aurorae at Jupiter’s poles, the result of the interaction between the solar wind and Jupiter’s huge magnetic field, also act as heat generators, heating the upper reaches of the atmosphere around the poles.

Chinese Fireworks Over Las Vegas

On Wednesday July 27th, people across the American south-west who happened to be outdoors on that evening were treated to the sight of a bright fireball crossing the night sky. Many caught the event on video, and the media quickly picked-up on the story as well, as videos were posted to YouTube and elsewhere. Initially it was thought the Delta Aquirid meteor shower was to blame – but frankly, the object was far to big and persistent to be the result of the shower.

The Fireball was seen across the south-western United States on the night of July 27th

The Fireball was seen across the south-western United States on the night of July 27th

It was Bad Astronomy guru Phil Plait who first recognised the culprit was far more human than cosmic, pointing a finger squarely at the Chinese National Space Agency. His findings were quickly confirmed by Jonathan McDowell, an astronomer at the Harvard-Smithsonian Centre for Astrophysics, who was able to show that the light show was the result of the upper stage of China’s new Long March 7 rocket re-entering the atmosphere.

As I reported at the time,  the Long March was launched for the first time on June 25th, 2016. It carried a 6-tonne Yuanzheng upper stage, which was used to place various payloads in orbit around the Earth, one of them being a sub-scale model of China’s next generation crew capsule to test its re-entry dynamics, a mission it completed on Sunday, June 26th.

The upper stage, although in a comparatively low orbit, stayed aloft somewhat longer, finally re-entering the atmosphere on July 27th. Travelling at some 20,000 Km/h (12,427 mph), its mass sufficient enough to create the fireball and trail as frictional heat caused it to burn-up and disintegrate. The largest segments of the vehicle are thought to have burned up at an altitude of around 100 km (63 miles).

NASA Approves Dream Chaser Cargo; Test Programme to Resume

In January, I wrote about NASA’s surprise decision to award an extended contract for resupply missions to  the International Space Station (ISS) 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, called Dream Chaser Cargo.

Dream Chaser Cargo is intended to deliver up to 5 tonnes of supplies (both pressurised and unpressurised material) to / from the space station and on July 26th, 2016, NASA formally approved Sierra Nevada’s development plans for Dream Chaser Cargo. As a result, formal ground and flight tests of the vehicle will resume later in 2016.

The Dream Chaser test article has now been modified for testing the Cargo variant of the vehicle. Credit: Sierra Nevada Corporation

The Dream Chaser test article has now been modified for testing the Cargo variant of the vehicle. Credit: Sierra Nevada Corporation

Prior to Sierra Nevada being ruled out of the commercial crew contract, a Dream Chaser test article vehicle had previously undergone a series of ground and tethered tests in 2012/13, prior to a free-fall test flight, marred only by the failure of the left landing wheel to deploy prior to landing. That test article vehicle has now been modified for cargo use and will be shipped NASA’s Armstrong Flight Research Centre in California, where it will resume its interrupted test schedule. These test will culminate in a further free-fall drop test in December 2016.

Providing this testing is successful, NASA will continue to support Sierra Nevada as the company expands testing and development of Dream Chaser Cargo in readiness for its first resupply mission to the ISS, which is provisionally scheduled for February 2019.

Has Ceres Had a Muddy Facial?

NASA’s Dawn mission, which I last wrote about back in April 2016, had been continuing to study the dwarf planet Ceres. Since its arrival around the little worldlet in March 2015, Dawn has shown us that Ceres is every bit as baffling to our view of small rocky bodies in the solar system as Pluto. One of the many mysteries Ceres has thrown at scientists is that, despite it being a very old body in the solar system, it is almost entire devoid of the kind of large impact craters one might expect to find on its surface.

Dawn has shown that Ceres appears to be almost absent any signs of really large impacts in its past - which has surprised scientists (Credit: SwRI)

Dawn has shown that Ceres appears to be almost absent any signs of really large impacts in its past – which has surprised scientists (Credit: SwRI)

To be sure, Ceres does have craters – a lot of them. But none are of a size one might expect to see on a body formed during the earliest period of the solar system’s evolution, when it would most likely have faced numerous and spectacular impacts. In fact, only three really large impact areas have been found on Ceres, but they are not as well-defined as should be the case, and given rise to all sorts of theories about Ceres’ early history.

However, a team studying the data returned by the mission believe they have the answer. The Dawn spacecraft has revealed very strong evidence for Ceres having a subsurface frozen “ocean” of briny ice and other material, and appears to be subject to “cryovolcanism”.  The science team therefore suggest that cryovolcanic activity early in Ceres’ history, coupled with those early impacts caused multiple eruptions of this subsurface material, which flowed out into the older craters, effectively giving Ceres a “mud pack facial”, eradicating the evidence of those ancient impacts, leaving it with a young-looking complexion.

 

Have any thoughts?

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s