News from Space: Rosetta Maps Comet Surface

Rosetta_and_Philae_at_cometLast month, the European Space Agency Rosetta’s space probe arrived at the comet known as 67P/Churyumov–Gerasimenko, thus becoming the first spacecraft to ever rendezvous with a comet. As it continues on its way to the Inner Solar System, Rosetta’s sensing instruments have been studying the surface in detail in advance of the attempted landing of it’s Philae probe.

Because of this, Rosetta has been able to render a map of the various areas on the surface of the comet, showing that it is composed of several different regions created by a range of forces acting upon the object. Images of the comet’s surface were captured by OSIRIS, the scientific imaging system aboard the Rosetta spacecraft, and scientists analyzing them have divided the comet into several distinct regions, each characterized by different classes of features.

rosettamap-1All told, areas containing cliffs, trenches, impact craters, rocks, boulders and parallel grooves have been identified and mapped by the probe. Some of the areas that have been mapped appear to be caused by aspects of the activity occurring in and around the nucleus of the comet, such as where particles from below the surface are carried up by escaping gas and vapor and strewn around the surface in the surrounding area.

So detailed are these images that many have been captured at a resolution of one pixel being equal to an area of 194 square centimeters (30 square inches) on the comet surface. Dr. Holger Sierks, OSIRIS’ Principal Investigator from the Max Planck Institute for Solar System Science, puts it into perspective:

Never before have we seen a cometary surface in such detail. It is a historic moment – we have an unprecedented resolution to map a comet… This first map is, of course, only the beginning of our work. At this point, nobody truly understands how the surface variations we are currently witnessing came to be.

Rosetta_and_Philae_at_comet_node_full_imageThe newly-generated comet maps and images captured by the instruments on Rosetta will now provide a range of detail on which to finalize possible landing sites for the Philae probe to be launched to the surface . As such, the Rosetta team will meet in Toulouse, France, on September 13 and 14 to allocate primary and backup landing sites (from a list of sites previously selected) with much greater confidence.

At the same time, Rosetta has revealed quite a bit about the outward appearance of the comet, and it aint pretty! More often than not, comets are described as “dirty snowballs” to describe their peculiar composition of ice and dust. But Rosetta’s Alice instrument, which was installed by NASA, has sent back preliminary scientific data that shows that the comet is more akin to a lump of coal.

Rosetta_Artist_Impression_Far_625x469Alice is one of eleven instruments carried aboard Rosetta and one of three instrument packages supplied by NASA for the unmanned orbiter. Essentially, it’s a miniature UV imaging spectrograph that looks for thermal markers in the far ultraviolet part of the spectrum in order to learn more about the comet’s composition and history. It does this by looking specifically for the markers associated with noble gases, such as helium, neon, argon, and krypton.

The upshot of all this high-tech imaging is the surprising discovery of what 67P/Churyumov-Gerasimenko looks like. According to NASA, the comet is darker than charcoal. And though Alice has detected oxygen and hydrogen in the comet’s coma, the patches of barren ice that NASA scientists had expected aren’t there. Apparently, this is because 67P/Churyumov-Gerasimenko is too far away from the warmth of the sun to turn the ice into water vapor.

rosetta-1Alan Stern, Alice principal investigator at the Southwest Research Institute in Boulder, Colorado, had this to say about the revelation:

We’re a bit surprised at just how unreflective the comet’s surface is and how little evidence of exposed water-ice it shows.

Launched in 2004, Rosetta reached 67P/Churyumov-Gerasimenko by a circuitous route involving three flybys of Earth, one of Mars, and a long detour out beyond Jupiter as it built up enough speed to catch up to the comet. Over the coming months, as the Rosetta spacecraft and comet 67P move further into the solar system and approach the sun, the OSIRIS team and other instruments on the payload will continue to observe the comet’s surface for any changes.

alice-first-findings-3Hence why this mission is of such historic importance. Not only does it involve a spacecraft getting closer to a comet than at time in our history, it also presents a chance to examine what happens to a comet as it approaches our sun. And if indeed it does begin to melt and breakdown, we will get a chance to peer inside, which will be nothing less than a chance to look back in time, to a point when our Solar System was still forming.

Sources: gizmag, (2), jpl.nasa.gov, nasa.gov

News From Space: Rosetta Starts, Orion in the Wings

 Quick Note: This is my 1700th post!
Yaaaaaay, happy dance!

Rosetta_Artist_Impression_Far_625x469Space exploration is a booming industry these days. Between NASA, the ESA, Roscosmos, the CSA, and the federal space agencies of India and China, there’s just no shortage of exciting missions aimed at improving our understanding of our Solar System or the universe at large. In recent months, two such missions have been making the news; one of which (led by the ESA) is now underway, while the other (belonging to NASA) is fast-approaching.

In the first instance, we have the ESA’s Rosetta spacecraft, which is currently on its way to rendezvous with the comet 67P/Churyumov-Gerasimenko at the edge of our Solar System. After awaking from a 957 day hibernation back in January, it has just conducted its first instruments observations. Included in these instruments are three NASA science packages, all of which have started sending science data back to Earth.

Rosetta_and_Philae_at_cometSince leaving Earth in March 2004, the Rosetta spacecraft has traveled more than 6 billion km (3.7 billion miles) in an attempt to be the first spacecraft to successfully rendezvous with a comet. It is presently nearing the main asteroid belt between Jupiter and Mars – some 500,000 km (300,000 miles) from its destination. And until August, it will executing a series of 10 orbit correction maneuvers to line it self up to meet with 67P, which will take place on August 6th.

Rosetta will then continue to follow the comet around the Sun as it moves back out toward the orbit of Jupiter. By November of 2014, Rosetta’s mission will then to launch its Philae space probe to the comet, which will provide the first analysis of a comet’s composition by drilling directly into the surface. This will provide scientists with the first-ever interior view of a comet, and provide them with a window in what the early Solar System looked like.

rosetta-1The three NASA instruments include the MIRO, Alice, and IES. The MIRO (or Microwave Instrument for Rosetta Orbiter) comes in two parts – the microwave section and the spectrometer. The first is designed to measure the comet’s surface temperatures to provide information on the mechanisms that cause gas and dust to pull away from it and form the coma and tail. The other part, a spectrometer, will measure the gaseous coma for water, carbon monoxide, ammonia, and methanol.

Alice (not an acronym, just a nickname) is a UV spectrometer designed to determine the gases present in the comet and gauge its history. It will also be used to measure the rate at which the comet releases water, CO and CO2, which will provide details of the composition of the comet’s nucleus. IES (or Ion and Electron Sensor) is one of five plasma analyzing instruments that make up the Rosetta Plasma Consortium (RPC) suite. This instrument will measure the charged particles as the comet draws nearer to the sun and the solar wind increases.

oriontestflightNamed in honor of the Rosetta Stone – the a basalt slab that helped linguists crack ancient Egyptian – Rosetta is expected to provide the most detailed information about what comets look like up close (as well as inside and out). Similarly, the lander, Philae, is named after the island in the Nile where the stone was discovered. Together, they will help scientists shed light on the early history of our Solar System by examining one of its oldest inhabitants.

Next up, there’s the next-generation Orion spacecraft, which NASA plans to use to send astronauts to Mars (and beyond) in the not too distant future. And with its launch date (Dec. 4th, 2014) approaching fast, NASA scientists have set out what they hope to learn from its maiden launch. The test flight, dubbed EFT-1 is the first of three proving missions set to trial many of the in-flight systems essential to the success of any manned mission to Mars, or the outer Solar System.

orionheatshield-1EFT-1 will take the form of an unmanned test flight, with the Orion spacecraft being controlled entirely by a flight control team from NASA’s Kennedy Space Center located in Florida. One vital component to be tested is the Launch Abort System (LAS), which in essence is a fail-safe required to protect astronauts should anything go wrong during the initial launch phase. Designed to encapsulate the crew module in the event of a failure on the launch pad, the LAS thrusters will fire and carry the Orion away from danger.

Orion’s computer systems – which are 400 times faster than those used aboard the space shuttle and have the ability to process 480 million instructions per second- will also be tested throughout the test flight. However, they must also demonstrate the ability to survive the radiation and extreme cold of deep space followed by the fiery conditions of re-entry, specifically in the context of prolonged human exposure to this dangerous form of energy.

oriontestflight-1Whilst all systems aboard Orion will be put through extreme conditions during EFT-1, none are tested as stringently as those required for re-entry. The entire proving mission is designed around duplicating the kind of pressures that a potential manned mission to Mars will have to endure on its return to Earth, and so naturally the results of the performance of these systems will be the most eagerly anticipated by NASA scientists waiting impatiently in the Kennedy Space Center.

Hence the Orion’s heat shield, a new design comprised of a 41mm (1.6-inch) thick slab of Avcoat ablator, the same material that protected the crew of Apollo-era missions. As re-entry is expected to exceed speeds of 32,187 km/h (20,000 mph), this shield must protect the crew from temperatures of around 2,204 ºC (4,000 ºF). Upon contact with the atmosphere, the heat shield is designed to slowly degrade, drawing the intense heat of re-entry away from the crew module in the process.

orionheatshield-2The final aspect of EFT-1 will be the observation of the parachute deployment system. Assuming the LAS has successfully jettisoned from the crew module following launch, the majority of Orion’s stopping power will be provided by the deploying of two drogue parachutes, followed shortly thereafter by three enormous primary parachutes, with the combined effect of slowing the spacecraft to 1/1000th of its initial re-entry speed.

Previous testing of the parachute deployment system has proven that the Orion spacecraft could safely land under only one parachute. However, these tests could not simulate the extremes that the system will have to endure during EFT-1 prior to deployment. The Orion spacecraft, once recovered from the Pacific Ocean, is set to be used for further testing of the ascent abort system in 2018. Data collected from EFT-1 will be invaluable in informing future testing, moving towards a crewed Orion mission some time in 2021.

oriontestflight-2NASA staff on the ground will be nervously monitoring several key aspects of the proving mission, with the help of 1,200 additional sensors geared towards detecting vibration and temperature stress, while taking detailed measurements of event timing. Furthermore, cameras are set to be mounted aboard Orion to capture the action at key separation points, as well as views out of the windows of the capsule, and a live shot of the parachutes as they deploy (hopefully).

The launch promises to be a historic occasion, representing a significant milestone on mankind’s journey to Mars. Orion, the product of more than 50 years of experience, will be the first human-rated spacecraft to be constructed in over 30 years. The Orion will be launch is expected to last four hours and 25 minute, during which time a Delta-2 Heavy rocket will bring it to an altitude of 5,794 km (3,600 miles) with the objective of creating intense re-entry pressures caused by a return from a deep space mission.

And be sure to check out this animation of the Orion Exploration Flight Test-1:

Sources: gizmag.com, (2)