上篇博文：印度发射火星探测器，先不要高兴这么早 2013-11-05

最新消息：印度火星探测器跌了一脚

正在环绕地球飞行的印度火星探测器因火箭推进器故障未能将飞船提升到预定高度。

11日，印度在对轨道高度进行调整，将轨道高度从7.8万公里提升到计划的10万公里时，火箭的液体燃料推进器出现故障，未能将重1350公斤的飞船推到预定高度。

火星探测器的助推发动机将在印度时间星期二（12日）凌晨5点再次点火助推，希望将探测器推到应有的高度。

印度广播网NDTV的科学事务主编巴格拉说，星期一凌晨的喷火助推消耗了2公斤燃料。该探测器的火箭共携带了852公斤液态燃料。巴格拉说，11月5日的发射如此精确，节省下6公斤的燃料。因此，即便出现了小挫折，仍有4公斤的燃料节余。

按计划，印度的火星探测器应在太空飞行300天后于2014年9月抵达火星轨道。2014年9月24日，飞船火箭助推器将再次点燃，降低飞船的速度，然后火星的引力将飞船引入火星轨道。

印度空间研究组织负责人说，火星探测器状态依然“健康”。

如果再出半点差错，多余的4公斤燃料将不够损失，也就是说，携带的干粮盘缠不够了。

持续关注中。

India's Mars Mission hits first hurdle

http://www.ndtv.com/article/india/india-s-mars-mission-hits-first-hurdle-444424

New Delhi: India's mission to Mars, launched last week, has hit its first problem. Last night, the satellite was not able to raise its orbit to the required 100,000 km.

India’s Mars Orbiter Mission (MOM) Requires Extra Thruster Firing after Premature Engine Shutdown

India’s Mars Orbiter Mission (MOM) probe suffered a surprise hiccup overnight (Nov. 11 IST) when the main engine shut down prematurely and left the country’s first ever mission to the Red Planet flying in a significantly lower than planned interim elliptical orbit around Earth – following what was to be her 4th orbit raising burn since last week’s flawless launch.

Indian Mars mission suffers glitch but 'no setback'

http://phys.org/news/2013-11-indian-mars-mission-glitch-setback.html

India's Mars spacecraft suffered a brief engine failure Monday as scientists tried to move it into a higher orbit around Earth, but controllers denied any setback to the ambitious low-cost mission.

India's Mars orbiter mission suffers glitch

http://www.financialexpress.com/news/indias-mars-mission-suffers-glitch-isro-says-spacecraft-healthy/1193535

Indian Mars mission hit by snag

http://www.bbc.co.uk/news/science-environment-24900271

India's mission to Mars has hit a snag, after a planned engine burn failed to raise the spacecraft's orbit around Earth by the intended amount.

The problem occurred during a manoeuvre designed to boost the craft's maximum distance from 71,623km to 100,000km.

A problem with the liquid fuel thruster caused the 1,350kg vehicle to fall short of the mark.

But the head of the Indian Space Research Organisation (Isro) said the spacecraft remained "healthy".

However, independent experts contacted by the BBC said they were puzzled by the stated circumstances surrounding the glitch.

his was the fourth in a series of five engine burns known as "midnight manoeuvres" because several constraints require that they are carried out in the early hours of the morning.

The failure of the test and the spacecraft's consequently reduced velocity raised the spacecraft's apogee (the point in its orbit farthest away from Earth) from 71,623km to just 78,276km - about 25% of the way to the target of 100,000km.

But independent experts approached by the BBC said they were baffled by how the coil test could have contributed to a loss of thrust.

"Using the primary and redundant coils of the [engine's] solenoid valve of itself should not necessarily lead to a lack of thrust," a source told me on condition of anonymity.

"It should be a configuration they will have tested on the ground, which may mean this lack of thrust is nothing to do with the coils and that it's another issue."

The source explained: "It's very strange," adding: "The redundant coil should not act against the primary one in any way."

Alternative causes could include one or both propellant valves failing to open within the engine, or a lack of propellant in the first case. The latter scenario could indicate a catastrophic fuel leak that would almost certainly spell the end for the mission. But there are reasons to doubt this failure mode because less powerful liquid fuel thrusters on the spacecraft continued to work during the burn, the expert said.

Another possible reason for the loss of thrust could have been melting in the combustion chamber during a previous firing that broke the fuel nozzle.

However, all eyes will now be on the next engine burn, which should clarify whether or not there are bigger concerns over the health of the spacecraft.

If the additional firing on Tuesday can successfully bridge the gap, a final midnight manoeuvre on 16 November will boost the apogee to 192,000km.

On 1 December, the engine will be fired again for its "trans-Martian injection", despatching the craft on a 300-day journey to Mars.

On 24 September next year, the engine will be fired again to slow down the spacecraft, enabling it to be captured by Mars' gravity and placed into orbit.

India's PSLV rocket - the second choice for the mission after a beefier launcher failed - was not powerful enough to send the MOM on a direct flight to Mars.

So engineers opted for a method of travel called a Hohmann Transfer Orbit to propel the spacecraft from Earth to Mars with the least amount of fuel possible.