When Asteroids Collide – Part II

Asteroid P/2010 A2 Image Credit: JPL / NASA

Previously, nssphoenix reported on the Hubble images of the comet / asteroid / debris trail pictured at left. Now, the European Space Agency (ESA) reports that it’s comet chasing spacecraft Rosetta has imaged the same object as shown in the spectacular Hubble pictures. Colin Snodgrass, at the Max Planck Institute for Solar System Research in Germany, decided to investigate the object using the Rosetta spacecraft because it was far from Earth and could look at the object from a completely different perspective.

The Image below was taken by the OSIRIS camera aboard the Rosetta spacecraft in March of 2010. It enabled scientists to confirm that the object is not a comet. Rather, computer modeling shows that the debris field was created in a single event.

Rosetta Image of Asteroid P/2010 A2
Image Credit: ESA / MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Dr Snodgrass and colleagues have concluded that the collision that produced the debris field occurred within a ten day period around 10 February 2009, almost a year before its discovery.

“We are really quite confident about that date because of the quality of the data we used”.

Jessica Agarwal, a former ESA research fellow, and other researchers have used the Hubble Space Telescope to resolve a single remaining asteroid, about 120 meters across, at the head of the trail (see the white dot in the first image above). Using this information, Dr. Snodgrass and his colleagues estimate that the asteroid destroyed in the collision was probably only a few meters in diameter.

If we could get a closeup of the remaining asteroid, we would see a brand new crater on the surface.

Images of Lutetia

Lutetia from 60,000 km. Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

The Rosetta spacecraft has now completed its fly-by of 21/Lutetia, discovered in 1852 by Hermann Goldschmidt from his Paris balcony. Lutetia was his first discovery, and the 21st confirmed asteroid. Goldschmidt would ultimately discover 13 more asteroids (Nos. 32,36,40,41,44,45,48,49,52,54,56,61 and 70). Following the fly-by of Lutetia, Rosetta is headed for comet 67P/Churyumov-Gerasimenko (C-G) in 2014. Rosetta will spend two years circling the comet and observing its behavior as C-G plunges from 500 million miles from the Sun to 120 million miles at perihelion,and then back out towards the orbit of Jupiter. While orbiting C-G, Rosetta will release Philae, designed to land on the comet. Below are the latest release of images from the Rosetta OSIRIS camera of the Asteroid Lutetia. Note the planet Saturn with its rings, sitting above the asteroid in the first image below, left. See previous posts on Lutetia and Rosetta: Rosetta Encounters Lutetia and Rosetta.

Closing on Lutetia with Saturn above. Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Leaving Lutetia – Night side. Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Lutetia Closest Approach Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Lutetia – Crater Close Up Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Lutetia – GroovesClose Up Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Let us know what you think. What do you want to know about? Post a comment.

Rosetta Encounters Lutetia

Artist Conception of Rosetta fly by of Asteroid Lutetia on 10 July 2010 Image Credit: ESA, image by C.Carreau See the previous post on Rosetta and Lutetia : Rosetta.

At 9:10 AM Phoenix time (16:10 UTC), Rosetta will make its closest approach to Lutetia. It will fly by at a separation of 3,200 kilometres, at a relative speed of 54,000 km/hr. They will be some 454 million km from Earth. Approximately two hours of high quality imaging will be recorded, which will be immediately piped back to Earth. The time of closest approach is currently estimated (8 July) at . The first images to be received back from the comet-chasing spacecraft Rosetta should occur at 2:00 PM Phoenix time (21:00UTC), when ESA resumes its media coverage (see schedule below). 21-Lutetia is a large main belt asteroid, and you can follow the event live at ESA, beginning at 9:00 AM Phoenix time (16:00 UTC). The ESA Media Schedule: 09:00:00 Start media event live from ESA/ESOC 09:05:07 Stop – radio communications via high-gain antenna – Loss of signal (earliest) 09:10:07 Closest approach to Lutetia 09:20:07 End asteroid closed-loop tracking 09:45:07 Resume radio communications via high-gain antenna – Acquisition of signal (latest) 09:47:00 Media event pause 11:05:35 Start science data downlink 14:00:00 Resume media event – Science team presents data 14:45:00 End media event

The latest image released by ESA shows Lutetia as seen from Rosetta. This image was acquired by Rosetta’s OSIRIS imaging system and shows asteroid 21 Lutetia from a distance of 2 million km, rapidly decreasing, and was acquired by the Narrow Angle Camera of OSIRIS on 8 July 2010 at around 6:00 PM Phoenix Time (9 July 2010 – 01:00 UTC). Loss of signal occurred at 9:06 AM Phoenix time. Closest approach has now occurred at 9:10 AM. At 9:20 AM, we are 30 minutes from reacquiring the Rosetta signal. Below is the latest image from Rosetta at 80,000 km from Lutetia. At 9:45 AM, we have telemetry from Rosetta. Congratulations. Telemetry indicates that the Rosetta spacecraft is healthy and performing nominally. Realtime numbers for Rosetta can be found at Daniel Muller’s web site.

Lutetia from 2 million kilometers Image Credit: SA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Explanation of the Lutetia Fly – by Image Credit: ESA TV Lutetia’s image on the right shows a resolution of about 2 kilometres per pixel, as was taken from about 60-80,000 kilometres. The asteroid is about 130 km by 85 km. Four hours from now we should get images with a resolution of about 60 metres per pixel. At this point, the ESA media event has paused. It will resume in about four hours. We will post images as they become available. At 10:40 AM Phoenix time, the science download has begun.

Lutetia from 60,000 km. Image Credit: (C) ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

Rosetta

Rosetta fly by of Asteroid Steins on 5 September 2008 Image Credit: ESA, image by C.Carreau

Space scientists will be on the edge of their seats this Saturday (10 July 2010) as they wait for the first images to be received back from comet-chasing spacecraft Rosetta as it makes its rendezvous with her second asteroid, 21-Lutetia. Lutetia is a large main belt asteroid. Follow the event live at ESA, beginning at 9:00 AM Phoenix time (16:00 UTC). Launched aboard an Ariane 5G rocket from Europe’s Spaceport in French Guiana in March of 2004, Rosetta is on a ten year mission to accompany comet 67P/Churyumov-Gerasimanko (or “C-G”) on its orbit around the Sun. The first objective of the three bodies to be studied by Rosetta was asteroid 2867 Šteins (image at right). 2867 Šteins is an E-type asteroid with a diameter of approximately 4.6 km. Its surface is thought to be largely magnesium silicate (MgSiO3), and similar to terrestrial basalts or plutonic rocks that have been differentiated and reprocessed by melting and recrystallization. Following its encounter with Šteins, Rosetta headed for its 10 July 2010 encounter with Lutetia.

When Rosetta reaches Lutetia, it will fly by at a separation of 3,200 kilometres, at a relative speed of 54,000 km/hr. They will be some 454 million km from Earth. Approximately two hours of high quality imaging will be recorded, which will be immediately piped back to Earth. The time of closest approach is currently estimated (8 July) at 9:10 AM Phoenix time (16:10 UTC), and the spacecraft’s accompanying lander, Philae, will be switched on earlier that day in order to collect data throughout the flyby. The Rosetta probe was built by EADS Astrium. Rosetta consists of a 3,065-kg spacecraft (1,578-kg dry mass) and a 100-kg lander, Philae. Rosetta will enter orbit around the nucleus of comet Churyumov-Gerasimenko in August 2014, following three gravity assists from Earth and one from Mars. Philae (excellent interactive graphic of the orbits and Rosetta accompanying C-G) was created by a European consortium under the leadership of the German Aerospace Research Institute (DLR). Other members of the consortium are ESA and institutes from Austria, Finland, France, Hungary, Ireland, Italy and the UK. After Rosetta‘s rendezvous with Lutetia, she will be off to Churyumov-Gerasimenko, a comet with a current orbital period of 6.6 years, and discovered accidentally in 1969. Based on the orbital parameters, it appears that in 1959 C-G was nudged by an encounter with Jupiter into its present orbit, with a perihelion of 1.28 AU This is sufficiently close to create a comet tail. Prior to this, C-G had a perihelion of 3.0 AU. This orbit was established by an encounter with Jupiter around 1840. Prior to that, the perihelion was 4.0 AU.

Rosetta Observing Lutetia Image Credit: ESA/ AOES Medialab.

The Rosetta Lander – Philae Image Credit: ESA

Here are the landmarks for Rosetta: Rosetta will be the first spacecraft to orbit a comet’s nucleus. It will be the first spacecraft to fly alongside a comet as it heads towards the inner Solar System. Rosetta will be the first spacecraft to examine from close proximity how a frozen comet is transformed by the warmth of the Sun. Shortly after its arrival at Comet 67P/Churyumov-Gerasimenko, the Rosetta orbiter will despatch a robotic lander for the first controlled touchdown on a comet nucleus. The Rosetta lander’s instruments will obtain the first images from a comet’s surface and make the first in situ analysis to find out what it is made of. On its way to Comet 67P/Churyumov-Gerasimenko, Rosetta will pass through the main asteroid belt, with the option to be the first European close encounter with one or more of these primitive objects. Rosetta will be the first spacecraft ever to fly close to Jupiter’s orbit using solar cells as its main power source. An extensive description of Philae can be found here (pdf).

The Rosetta orbiter has eleven scientific instruments: ALICE Ultraviolet Imaging Spectrometer CONSERT Comet Nucleus Sounding COSIMA Cometary Secondary Ion Mass Analyser GIADA Grain Impact Analyser and Dust Accumulator MIDAS Micro-Imaging Analysis System MIRO Microwave Instrument for the Rosetta Orbiter OSIRIS Rosetta Orbiter Imaging System ROSINA Rosetta Orbiter Spectrometer for Ion and Neutral Analysis RPC Rosetta Plasma Consortium (one of the five instruments is IES) RSI Radio Science Investigation VIRTIS Visible and Infrared Mapping Spectrometer 67P/Churyumov-Gerasimenko Image Credit: ESA, image by AOES Medialab

The Lander Philae has 10 instruments. APXS – Alpha Proton X-ray Spectrometer – analyzes the chemical element composition of the surface below the lander. The instrument is an improved version of the APXS of the Mars Pathfinder. COSAC – The COmetary SAmpling and Composition – The combined gas chromatograph and time of flight mass spectrometry will perform analysis of soil samples and determine the content of volatile components. Ptolemy – an Instrument to Measure Stable Isotopic Ratios of Key Volatiles on a Cometary Nucleus. ÇIVA – Comet Nucleus Infrared and Visible Analyzer. ROLIS – Rosetta Lander Imaging System. CONSERT – COmet Nucleus Sounding Experiment by Radiowave Transmission -The Consert radar will perform the tomography of the nucleus by measuring electromagnetic wave propagation from Philae and the Rosetta probe throughout the comet nucleus in order to determine its internal structures and to deduce information on its composition. MUPUS – MUlti-PUrpose Sensors for Surface and Sub-Surface Science. ROMAP (Rosetta Lander Magnetometer and Plasma Monitor. SESAME – Surface Electric Sounding and Acoustic Monitoring Experiment. SD2 – The sampling, drilling and distribution subsystem.

Timeline (from NASA): On March 2, 2004, Rosetta was launched into an orbit that enabled it to chase Earth around the Sun for about a year. On March 4, 2005, Rosetta caught up with Earth and executed the first of its four gravity assists (three from Earth and one from Mars). This first gravity assist hurled Rosetta toward Mars for its meeting in 2007. En route to Mars, Rosetta’s instruments analyzed the collision between Deep Impact’s impactor and comet Tempel-1 on July 4, 2005. In February 2007, Rosetta executed a close flyby of Mars, which provided the gravity assist it needed to loop back toward Earth for a second flyby in November 2007. In November 2007, Rosetta will execute its second Earth flyby, gaining the gravity assist it needs to pass Mars’ orbit and reach the asteroid belt. On September 5, 2008, Rosetta will pass within 1700 km of asteroid Steins, enabling its instruments to closely observe the flying rock. In November, 2009, Rosetta will swing back for a final boost from Earth’s gravity to return again to the asteroid belt. On July 10, 2010, Rosetta will fly within 3000 km of asteroid Lutetia, and again use its instruments to observe at close range this asteroid, ten times larger than Steins. By May, 2011, Rosetta will be coasting through areas in the outer solar system where the sun is almost a billion km away. At that distance, Rosetta’s solar panels will not be able to gather much energy from the Sun, so the spacecraft will shut down most electrical activities and hibernate until comet C-G returns from its long transit in the outer solar system. In January 2014, Rosetta will fire its engine to position itself next to comet C-G in May 2014 as it comes hurtling by. Rosetta will release the Philae for a controlled soft landing on the comet. The Philae will then transmit critical data from the comet’s surface for relay back to Earth. Philae will use harpoons to anchor itself to the comet. After escorting comet C-G past its perihelion (closest point to the Sun), Rosetta will terminate its mission.

Rosetta – Final Fly-By

Credit: ESA Image

The European Space Agency (ESA) spacecraft Rosetta will make its third and final flyby of the Earth a month from now. Rosetta will swing by Earth on 13 November and begin the final leg of its 10-year journey to the outer Solar System. Several observations of the Earth–Moon system are planned before the spacecraft heads out to study comet 67/P Churyumov-Gerasimenko.

A summary of the mission from ESA reads: The International Rosetta Mission was approved in November 1993 by ESA’s Science Programme Committee as the Planetary Cornerstone Mission in ESA’s long-term space science programme. The mission goal was initially set for a rendezvous with comet 46 P/Wirtanen. After postponement of the initial launch a new target was set: Comet 67 P/Churyumov- Gerasimenko. On its 10 year journey to the comet, the spacecraft will pass by two asteroids: 2867 Steins (in 2008) and 21 Lutetia (in 2010). The ESA Rosetta blog has been reactivated. The latest entry is here.

Credit: ESA Image of Approach to Steins

History

• February 2004, Rosetta was launched by an Ariane-5 launch from Kourou in French Guiana.
• March 2005, Rosetta makes its first fly-by of Earth, and heads toward Mars.
• February 2007, Rosetta makes its fly-by of Mars
• November 2007, Rosetta makes its second fly-by of Earth, and heads toward the asteroid belt.
• September 2008, the Rosetta spacecraft encounters asteroid (2867) Steins.
• November 2009, third Earth fly-by.
• July 2010, Rosetta will encounter asteroid 21 Lutetia.
• May 2011 – January 2014, Rosetta goes into hibernation on the way to comet 67 P/Churyumov- Gerasimenko.
• May 2014, Rosetta arrives in the vicinity of comet 67 P/Churyumov- Gerasimenko and goes into orbit.
• Rosetta observes the comet on its plunge toward the sun, deploying the lander

Credit: ESA Image

The Rosetta orbiter has eleven scientific instruments: ALICE Ultraviolet Imaging Spectrometer CONSERT Comet Nucleus Sounding COSIMA Cometary Secondary Ion Mass Analyser GIADA Grain Impact Analyser and Dust Accumulator MIDAS Micro-Imaging Analysis System MIRO Microwave Instrument for the Rosetta Orbiter OSIRIS Rosetta Orbiter Imaging System ROSINA Rosetta Orbiter Spectrometer for Ion and Neutral Analysis RPC Rosetta Plasma Consortium RSI Radio Science Investigation VIRTIS Visible and Infrared Mapping Spectrometer

The Rosetta lander has nine scientific instruments: APXS Alpha Proton X-ray Spectrometer ÇIVA / ROLIS Rosetta Lander Imaging System CONSERT Comet Nucleus Sounding COSAC Cometary Sampling and Composition experiment MODULUS PTOLEMY Evolved Gas Analyser MUPUS Multi-Purpose Sensor for Surface and Subsurface Science ROMAP RoLand Magnetometer and Plasma Monitor SD2 Sample and Distribution Device SESAME Surface Electrical and Acoustic Monitoring Experiment, Dust Impact Monitor

Credit: ESA Image