“Dreams of Other Worlds”: Stardust and SOHO #WSW2013

Houston, we have lift off!

All week long for World Space Week, we will be posting exclusive excerpts from Chris Impey and Holly Henry’s new book, Dreams of Other Worlds: The Amazing Story of Unmanned Space Exploration. Each day will include an excerpt from a different chapter(s) about a different unmanned spacecraft, along with a picture of the craft that doubles as an iPhone background!

Today we have two excerpts. The first is from Chapter 6, and our excerpt talks about how Stardust was able to keep up with the intense speed of the Wild 2 comet to photograph it. The second excerpt is from Chapter 7, which describes “space weather”, which SOHO is able to track to warn us of any changes in our solar system.

Tomorrow will bring another chapter and another adventure, so stay tuned!

StardustMission controllers tried to sneak up behind Wild 2 to minimize the relative speed of the two objects. Even so Stardust was moving 13,000 mph, or five times the speed of a rifle bullet, as it flew through the glowing coma of the comet. It took seventy-two close-up photographs. That may not seem like many, but keeping the relatively small comet in the camera field of view during such a fleeting and high-speed encounter was a major feat.10 The images showed a surface riddled with depressions with flat bottoms and sheer walls, ranging in size from dozens of meters to several kilometers. The comet itself is irregular in shape and five kilometers in diameter. The features are impact craters and gas vents; ten vents were active when Stardust flew by.
The neatest trick Stardust had up its sleeve was gathering material from the comet tail. [...] All of the solid objects in the universe were built from microscopic dust particles—stardust. The probe was designed to capture material too small to see in its eight-minute ride through the comet’s tail and then its long ride home.
SOHOData from SOHO, and increasing concern over the impact of space weather, caused NASA to commission a new study in 2009. The resulting report provides clear economic data to quantify the risk to the near-Earth environment from episodes of intense solar activity. Extreme space weather is in a category with other natural hazards that are rare but have far-reaching consequences, like major earthquakes and tsunamis.34 It’s likely that more than once in the next twenty years there will be an “electro-jet disturbance” that disrupts the national power grid. In the 1989 event, the loss of some portions of the grid put stress on others and led to a cascade affect. The end result was power outages affecting more than 130 million people and covering half the country.
SOHO cannot prevent these natural disasters, but it can give two or three days’ notice of Earth-directed disturbances. And as we become more accurate in anticipating space storms, operators can place satellites in protective modes, shut down or limit power grids, redirect commercial flights, warn oceanic cruise and cargo ships, and place astronauts working on the International Space Station in the safest possible location on the station. Such steps will not only save lives but also protect the information systems that sustain our electronically fragile and networked global community.

Think you know all about these missions? Take our quiz and find out!
Proud of your score? Tweet it! #WSW2013

“Dreams of Other Worlds”: The Mars Rovers #WSW2013

MERHouston, we have lift off!

All week long for World Space Week, we will be posting exclusive excerpts from Chris Impey and Holly Henry’s new book, Dreams of Other Worlds: The Amazing Story of Unmanned Space Exploration. Each day will include an excerpt from a different chapter about a different unmanned spacecraft, along with a picture of the craft that doubles as an iPhone background!

Today’s excerpt is from Chapter 3, and it talks about our strategy for learning more about Mars, and what the Mars Rovers, Spirit and Opportunity, are doing to help us with that.

Tomorrow will bring another chapter and another adventure, so stay tuned!

Decoding the Red Planet

As we saw in the last chapter, Mars seems dead to the orbiters that daily send back images of the surface. The atmosphere is tenuous, ultraviolet radiation and cosmic rays scorch the soil, and it rarely gets above freezing even on the balmiest summer day.15 It’s unlikely any form of life could exist on the surface now, but Mars has not always been so inhospitable. NASA’s strategy in searching for life in the Solar System is to “follow the water,” and even if there’s no surface water now, there was in the past. Each of the Mars Exploration Rovers, Spirit and Opportunity, was designed for just a ninety-day mission. In the end, they have vastly exceeded expectations with their indomitable traverses of the forbidding Martian terrain. Think of them as twin robotic field geologists whose primary goal is to search for the signposts of water.16 The record of past water can be found in the rocks, minerals, and landforms on Mars, particularly those that could only have formed in the presence
of water.

Think you know all about these missions? Take our quiz and find out!
Proud of your score? Tweet it! #WSW2013

“Dreams of Other Worlds”: A Chapter A Day #WSW2013

VikingHouston, we have lift off!

All week long for World Space Week, we will be posting exclusive excerpts from Chris Impey and Holly Henry’s new book, Dreams of Other Worlds: The Amazing Story of Unmanned Space Exploration. Each day will include an excerpt from a different chapter about a different unmanned spacecraft, along with a picture of the craft that doubles as an iPhone background!

Today’s excerpt is from Chapter 2, and it discusses what it was like when, in 1976, we first landed a spacecraft on Mars.

Tomorrow will bring another chapter and another adventure, so stay tuned!

The Vikings Reach Mars

On July 20, 1976, a small spacecraft emerged from a cloudless, apricot-colored Martian sky and fell toward the western Chryse Planitia, the “Golden Plain.” Its heat shield glowed as it buffeted through the tenuous atmosphere.27 About four miles up, the parachutes deployed, the heat shield was jettisoned, and three landing legs unfolded like a claw. At one mile up, the retrorockets fired, and less than a minute later the Viking 1 lander decelerated to six miles per hour, reaching the surface with a slight jolt.28 It was a landmark of technological prowess, the first time humans had ever soft-landed an emissary on another planet.
The twin Viking missions were the most complex planetary probes ever designed. Their total price tag was around $1 billion, equivalent to $4 billion today after adjusting for inflation. That can be compared to the $80 million cost of Mariner 4. Mission planners were well aware of the challenges; the Soviets had previously failed four times to soft land on Mars.29 Each Viking consisted of an orbiter designed to image the planet and a lander equipped to carry out detailed experiments on the surface.30 For the most part, the hardware worked flawlessly, but there were tense moments for the engineers and scientists on the team. After ten months and 100 million miles of traveling, the Vikings reached Mars two weeks apart.

Think you know all about these missions? Take our quiz and find out!
Proud of your score? Tweet it! #WSW2013