Archive for the ‘Space’ Category

Maven to enter Mars orbit tonight and MOM on Wednesday

September 21, 2014

UPDATE:

NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars’ orbit at 10:24 p.m. EDT Sunday, Sept. 21, where it now will prepare to study the Red Planet’s upper atmosphere as never done before. MAVEN is the first spacecraft dedicated to exploring the tenuous upper atmosphere of Mars.

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NASA’s Maven will be inserted into Mars orbit later tonight at 2130 pm Eastern time and will be covered live by NASA TV.

India’s MOM should be inserted into Mars Orbit on Wednesday.

(Related: Alternate paths to Mars: NASA’s MAVEN compared to India’s MOM)

Maven planned Mars orbit insertion 20140921 - NASA

Maven planned Mars orbit insertion 20140921 – NASA

The orbit insertion factsheet from NASA is here: MAVEN Orbit Insertion Fact Sheet – NASA

The orbit-insertion maneuver will begin with the brief firing of six small thruster engines to steady the spacecraft. The engines will ignite and burn for 33 minutes to slow the craft, allowing it to be pulled into an elliptical orbit with a period of 35 hours.

Following orbit insertion, MAVEN will begin a six-week commissioning phase that includes maneuvering the spacecraft into its final orbit and testing its instruments and science-mapping commands. Thereafter, MAVEN will begin its one-Earth-year primary mission to take measurements of the composition, structure and escape of gases in Mars’ upper atmosphere and its interaction with the sun and solar wind….

MAVEN launched Nov. 18, 2013, from Cape Canaveral Air Force Station in Florida, carrying three instrument packages. It is the first spacecraft dedicated to exploring the upper atmosphere of Mars. The mission’s goal is to determine how the loss of atmospheric gas to space played a role in changing the Martian climate through time.

ISRO’s press briefing for the MOM Mars orbit insertion is here: MOM press briefing on Mars Orbit Insertion

MOM Mars Orbit insertion planned for 20140924  ISRO

MOM Mars Orbit insertion planned for 20140924 ISRO

It’s coming, but don’t invest just yet in mining Helium-3 on the moon

August 16, 2014

Helium (4He) is the second most abundant element in the known Universe (after hydrogen) but only makes up 5.2 parts per million (ppm) of the Earth’s atmosphere. Helium-3 (3He) is an isotope of helium with two protons and one neutron. It is not radioactive and very rare on Earth (7 parts per trillion) but exists in recoverable concentrations in the lunar topsoil (in the top 2 -3 m of lunar regolith). It is even more abundant on the gas giants Jupiter, Saturn, Uranus and Neptune.

Lunar soil sample #75501 brought back by Apollo 17 in 1972 revealed the presence of He-3 and since then every country planning moon missions has the vision of mining for 3He on the moon and of vast quantities of energy production by means of a aneutronic fusion process on earth. (For old fogies like me, 1972 was the year of Watergate!)

In fusion reactions neutrons are “nasty”. They are very hard to contain and make other materials radioactive on collision. The first generation fuels of Deuterium and Tritium (reactions 1 and 2 below) produce many neutrons. A second generation with Deuterium and 3He only produces a few. A 3He – 3He reaction would produce none.

Kulcinski: Fusion Energy could provide that new energy source in the middle of the 21st Century. ….. However, ……  the DT Tokamak does not appear to be the ultimate answer. The problem lies in both the DT fuel cycle, which emits 80% of its energy in highly damaging and radioisotope producing neutrons, and in the complex design of the Tokamak.

fusion reactions after Kulcinski

fusion reactions after Kulcinski

But the promise of having 3He available to produce power is immense.

(more…)

MOM and MAVEN approach Mars

August 12, 2014

Both the Indian Mars Orbiter Mission (MOM – Mangalyaan, budget $70 million) and NASA’s MAVEN (budget $672 million) are now approaching Mars. Both are doing well according to their latest status updates.

MOM was launched on 5th November last year and MAVEN on 18th November, 2013. Whereas MAVEN on its Atlas 5 rocket could directly enter into a  Hohmann Transfer Orbit with periapsis at Earth’s orbit and apoapsis at the distance of the orbit of Mars, MOM had to take the low-cost, scenic route. Because of the relatively low payload capability of the PSLV launch rocket, MOM had to spend 26 days in ever-increasing earth orbits. MOM had to fire its Liquid Motor six times to work its way up to departing Earth orbit using a standard Hohmann Transfer Orbit on 1st December.

Alternate paths to Mars: NASA’s MAVEN compared to India’s MOM

MAVEN - MOM trajectories

MAVEN – MOM trajectories

 

When they were launched MAVEN was expected to reach Mars on 22nd September 2014 and MOM 2 days later on 24th September 2014. The time lines have shifted slightly subsequent to the mid-course corrections carried out and MOM is now expected to reach Mars orbit about a week ahead of MAVEN. I suspect that the time of Mars Orbit Insertion is still a little fluid, but both are about 1 month away. MOM is currently about 6 minutes away in radio signal distance.

Discovery News:

India’s Mars Orbiter Mission (MOM) is more than 80 percent of the way to Mars and performing well, according to a Facebook update posted July 21 by the Indian Space Research Organization. MOM is expected to enter orbit on Sept. 14.

The second craft, NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN), is also performing well. MAVEN is scheduled to embark on its final approach to the Red Planet on Sept. 21, one week after MOM’s arrival, principal investigator Bruce Jakosky said. After months of checkouts and tests, the spacecraft will now be left quiet until close to the big day.

NASA’s MAVEN has now gone into a “pre-Mars Orbit Insertion moratorium.” All systems required for a safe Mars Orbit Insertion remain powered on. But other systems like the instruments are shut down until late September because they are not needed for a successful MOI. We want the spacecraft system to be as “quiet” as possible and in the safest condition during the critical event on September 21st”.

Related: Frugal engineering for India’s Mars mission

Rosetta finds its new stone

August 8, 2014

The Original Rosetta Stone – BBC

The new stone is a comet identified as 67P/Churyumov-Gerasimenko

  • It was first observed in 1969 and named after its Russian discoverers
  • The comet is in an elliptical 6.45-year orbit that takes it from beyond Jupiter at its furthest point, to between the orbits of Mars and Earth at its closest to the Sun.
  • It is approximately 3.5 x 4 km in size, has a rotational period of 12.7 hours and a mass of 3.14±0.21×1012 kg
  • The surface temperature appears to be around -70ºC, which is warmer than expected
  • It is currently about 405 million km from earth (about 22.5 light-minutes) and moving at 55,000 km/hr

The European Space Agency’s Rosetta craft has now arrived at 67P/Churyumov-Gerasimenko after a 10 year, 6.4 billion km long journey and has entered orbit around its new stone

Rosetta is a cornerstone mission to chase, go into orbit around, and land on a comet. It will study the Jupiter-family comet 67P/Churyumov-Gerasimenko with a combination of remote sensing and in situ measurements. The spacecraft will orbit the comet and release the Philae lander, which carries a suite of instruments for imaging and sampling the comet nucleus. The mission will track the comet through perihelion, examining its behaviour before, during and after.

Rosetta Trajectories by Christian Simoes astronoo.com

Rosetta Trajectories by Christian Simoes astronoo.com

The spacecraft was launched from Kourou aboard an Ariane 5G+ on 2 March 2004. It required four gravity assists for its journey, one by Mars and three by Earth. Rosetta had already flown by the asteroids 2867 Steins (in 2008) and 21 Lutetia (in 2010), before entering deep space hibernation in June 2011.

Rosetta’s main goals will be reached in 2014. Following a planned exit from hibernation on 20 January, the spacecraft’s instruments were checked as it continued on its journey to 67P/Churyumov-Gerasimenko. The spacecraft arrives at the comet in August 2014, and deploys the lander in November 2014.

Comet 67P-CG on 3rd August 2014 ESA

Comet 67P-CG on 3rd August 2014 ESA

Rosetta is just 100 km from the comet’s surface, but it will edge closer still. Over the next six weeks, it will describe two triangular-shaped trajectories in front of the comet, first at a distance of 100 km and then at 50 km.

At the same time, more of the suite of instruments will provide a detailed scientific study of the comet, scrutinising the surface for a target site for the Philae lander.

100 days to Mars for ISRO’s Mangalyaan

June 16, 2014

Four days ago

  • The second Trajectory Correction Manoeuvre (TCM-2) of India’s Mars Orbiter Spacecraft was successfully performed on June 11, 2014 at 1630 hrs IST. TCM-2 was performed by firing the spacecraft’s 22 Newton thrusters for a duration of 16 seconds.
  • At present, the radio distance between the Spacecraft and the Earth is 102 million km. A radio signal from the Earth to the Spacecraft now takes about 340 seconds. The spacecraft so far has traveled a distance of 466 million km as part of its total Journey of 680 million km.
  • ISRO is continuously monitoring Mars Orbiter Spacecraft using Indian Deep Space Network (IDSN). The spacecraft and its five scientific instruments are in good health.

And 100 days from today on 24th September, ISRO’s frugally engineered  Mars Orbiter Mission (called Mangalyaan meaning Mars craft) should be inserted into Mars orbit. The highly over-rated movie “Gravity” had a larger budget at $100 million than ISRO’s $75 million for its Mars mission.

China’s Jade Bunny apparently stuck on the moon

January 26, 2014

(I see that Chinese news reports usually translate “Yutu” as “Jade Rabbit” but from this version of the legend I prefer “Jade Bunny” as being more appropriate to the lunar creatures who went to Chang’e’s assistance and where the reincarnation of her husband Hou Yi was the Jade Bunny)

In a setback – apparently due to the difficult lunar terrain, the Jade Bunny lunar rover has suffered a “mechanical control abnormality” – which I take to mean that it is stuck and not responding to commands. China Daily has the story

China’s moon rover, Yutu (Jade Rabbit), has experienced a mechanical control anomaly, and scientists are organizing repairs. The abnormality occurred due to “complicated lunar surface environment,” the State Administration of Science, Technology and Industry for National Defence (SASTIND) said on Saturday, without giving further details. The abnormality emerged before the rover entered its second dormancy at dawn on Saturday asthe lunar night fell, according to SASTIND.

The lander, another part of the Chang’e-3 probe, also “fell asleep” earlier on Friday. The pair went dormant for two weeks about one month ago when the first lunar night of the mission occurred.

 ….. The Chang’e-3 lunar probe soft-landed on the Moon on December 14. Yutu separated from the lander hours later.

The success of the Chang’e-3 mission makes China the third country to soft-land a spacecraft on lunar soil after the United States and the former Soviet Union.

Lunar panorama: Chang’e 3 lander in Out of this World

Jade Bunny on the moon on 22nd December 2013 (photo Xinhua)

Jade Bunny on the moon on 22nd December 2013
(photo Xinhua)

Poltergeists on Mars

January 21, 2014

Mysterious forces and poltergeists are at work  on Mars (which in due course will be found not to be so mysterious after all). But stories about moving rocks, and possible aliens are not new. The latest however is just doing the rounds based on the pictures SOL 3528 and 3540.

Rock appears mysteriously in front of Mars Opportunity rover

Rock appears mysteriously in front of Mars Opportunity rover

(Phys.org)The lead scientist for NASA’s Mars rover exploration team (Steve Squyres) has announced that recent images beamed back by the Opportunity rover show a rock sitting in a place nearby where there wasn’t one just twelve days prior. The image, he says, has caused quite a commotion with the rover team as possible explanations for the sudden appearance of the rock are bandied about. The announcement was part of a meeting at California Institute of Technology to celebrate a decade of service by the tiny rover. …… 

….. How it got there has NASA’s best scratching their heads. Thus far, they have two main likely explanations: either the rock was tossed to that spot after a meteorite impact nearby, or far more likely, it came to rest there as a result of clumsy maneuvering by Opportunity itself. The rover is having trouble getting around these days as one of its actuators has failed. This means one wheel winds up scrapping the ground during turns, producing what Squyres described as “chatter” which he said could have caused some debris to be flung to where the rock is now.

But these stories have been appearing since – at least – about 2009 (based for example on pictures SOL 1833 onwards). Moving rocks on Mars have a long history of fanciful – and some not so fanciful – notions. A whole bunch can be found here and here. But it would seem that most of the conspiracy theories and “Life on Mars” stories are connected to the selling of particular books.

As far as stories are concerned, the first ever fictional account of Mars was probably Across the Zodiac (1880) by Percy Greg. But for me, The War of the Worlds (published in 1898) by H. G. Wells  and Edgar Rice Burroughs and his Martian Trilogy – published between 1912 and 1943 and which I first read in 1959 – are not easily surpassed.

Rosetta awakes

January 21, 2014

The European Space Agency is – justifiably – feeling pleased with itself:

Rosetta wake-up signal

It was a fairy-tale ending to a tense chapter in the story of the Rosetta space mission this evening as ESA heard from its distant spacecraft for the first time in 31 months.

Rosetta is chasing down Comet 67P/Churyumov-Gerasimenko, where it will become the first space mission to rendezvous with a comet, the first to attempt a landing on a comet’s surface, and the first to follow a comet as it swings around the Sun.

Since its launch in 2004, Rosetta has made three flybys of Earth and one of Mars to help it on course to its rendezvous with 67P/Churyumov-Gerasimenko, encountering asteroids Steins and Lutetia along the way.

Operating on solar energy alone, Rosetta was placed into a deep space slumber in June 2011 as it cruised out to a distance of nearly 800 million km from the warmth of the Sun, beyond the orbit of Jupiter.

Now, as Rosetta’s orbit has brought it back to within ‘only’ 673 million km from the Sun, there is enough solar energy to power the spacecraft fully again.

Thus today, still about 9 million km from the comet, Rosetta’s pre-programmed internal ‘alarm clock’ woke up the spacecraft. After warming up its key navigation instruments, coming out of a stabilising spin, and aiming its main radio antenna at Earth, Rosetta sent a signal to let mission operators know it had survived the most distant part of its journey.

The signal was received by both NASA’s Goldstone and Canberra ground stations at 18:18 GMT/ 19:18 CET, during the first window of opportunity the spacecraft had to communicate with Earth. It was immediately confirmed in ESA’s space operations centre in Darmstadt and the successful wake-up announced via the @ESA_Rosetta twitter account, which tweeted: “Hello, World!”

Rosetta will be woken up Monday at 1000GMT after a two-and-a-half year sleep

January 19, 2014

The European Space Agency will try and wake-up its sleeping Rosetta spacecraft on Monday at 1000 GMT. The spacecraft entered deep space hibernation in June 2011 when it was too far away from the sun to capture much solar energy. If this works it will be a considerable achievement considering that Rosetta was launched 10 years ago  and the communications technology on board is effectively at least two  “generations” old!

Rosetta trajectory till June 2011

ESA:

At 10:00 GMT on Monday, the most important alarm clock in the Solar System will wake up ESA’s sleeping Rosetta spacecraft.

Rosetta is chasing comet 67P/Churyumov–Gerasimenko and, since its launch in 2004, has made three flybys of Earth and one of Mars to build up enough speed and get on a trajectory towards the comet. It has also encountered asteroids Steins and Lutetia along the way.

Operating on solar energy alone, the spacecraft was placed into a deep space slumber in mid-2011 as it cruised far from the Sun and out towards the orbit of Jupiter. To prepare for its long sleep, Rosetta was oriented so that its solar arrays faced the Sun and put into a once per minute spin for stability.

The only devices left running were its computer and several heaters.

Thirty-one months later, Rosetta’s orbit has brought it back to within ‘only’ 673 million kilometres of the Sun, and there is finally enough solar energy to power the spacecraft fully again. It is time to wake up.

Rosetta’s computer is programmed to carry out a sequence of events to re-establish contact with Earth on 20 January, starting with an ‘alarm clock’ at 10:00 GMT.

Immediately after, the spacecraft’s startrackers will begin to warm up, taking around six hours.

Then its thrusters will fire to stop the slow rotation. A slight adjustment will be made to Rosetta’s orientation to ensure that the solar arrays are still facing directly towards the Sun, before the startrackers are switched on to determine the spacecraft’s attitude.

Once that has been established, Rosetta will turn directly towards Earth, switch on its transmitter and point its high-gain antenna to send its signal to announce that it is awake.

Because of Rosetta’s vast distance – just over 807 million kilometres from Earth – it will take 45 minutes for the signal to reach the ground stations. The first opportunity for receiving a signal on Earth is expected between 17:30 GMT and 18:30 GMT.

Graphic of mission

Rosetta Mission (ESA via BBC)

A garbage disposal system for space junk

January 17, 2014

NASA keeps track of all the debris in orbit. About 13,000 known objects are bigger than 10 centimeters in diameter and there are more than 100,000 pieces of orbital debris between 1 cm and 10 cm. Pieces smaller than 1 cm number in the tens of millions. All pieces of debris larger than 10 cm are carefully tracked using radar and telescopes.

Many schemes have been proposed for trying to get rid of space debris orbiting the Earth. The schemes have ranged from space harpoons, clouds of of ballistic gas, housekeeping, robotic satellites and laser cannon. The Japanese have a plan for an electrodynamic tether to be attached to the debris by a robot arm. the tether then generates an electric field as it orbits around the Earth and the magnetic field then encourages the debris to drop into lower orbits and eventually burn up. A tether is going to be sent up into space at the end of February for a trial.

Electrodynamic tether

SpaceDaily: Researchers at The Japan Aerospace Exploration Agency (JAXA) have developed what they called an electrodynamic tether made from thin wires of stainless steel and aluminium.

The idea is that one end of the strip will be attached to one of the thousands of dead satellites or bits of rocket that are jamming up space and endangering working equipment.

The electricity generated by the tether as it swings through the Earth’s magnetic field is expected to have a slowing effect on the space junk, which should, scientists say, pull it into a lower and lower orbit.

Eventually the detritus will enter the Earth’s atmosphere, burning up harmlessly long before it has chance to crash to the planet’s surface.

“The experiment is specifically designed to contribute to developing a space debris cleaning method,” said Masahiro Nohmi, associate professor at Kagawa University, who is working with JAXA on the project, told AFP. Nohmi said a satellite developed by the university is expected to be launched into space on February 28, with the tether aboard.

“We have two main objectives in the trial next month,” he said. “First, to extend a 300-metre (1,000-foot) tether in orbit and secondly to observe the transfer of electricity.” The actual reeling in of orbiting rubbish will be the objective of future experiments, he said. A spokesman for JAXA said the agency also plans to conduct its own trial on a tether in 2015.

More than 20,000 bits of cast off equipment, including old satellites, pieces of rocket and other fragments are uselessly orbiting the Earth in a band 800-1,400 kilometres (500-900 miles) from the surface of the planet at terrific speed. 

JAXA write:

If we are able to calculate the motion of debris, we can attach a propulsion system for removal. As the propulsion system, we have envisioned an “electrodynamic tether”, which is extremely efficient because it does not require fuel. The end of an electrically conductive cord (tether) is attached to the debris, transferring it to a lower orbit through the Lorentz force generated by the interference between Earth’s magnetic field and the current flowing through the tether, causing it to re-enter the atmosphere. Two methods are being considered for attaching the tether. One is a method of using a robot arm, for example, to hook the end of the tether into a 1-meter-diameter hole in a payload attachment fitting used as a base for mounting the satellite onto the rocket.  Another is a method where the side of the rocket stage, which is extremely thin for reduced weight, is approached and harpooned by the tether end to attach it. This method is considered to be a safer operation since the tether can be attached from a distance of 10 to 20m.


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