Looking to the USA

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The USA still holds a leading position within space activities in spite of decreasing budgets in recent years. The level of activities is still very high and new space projects at different sizes are constantly being developed, built and launched.

To follow the space activities in the USA is therefore an extensive activity and can only partly be followed in detail.

Two years ago, We travelled to several research institutes in the USA, and among several projects we were introduced to are the following; The Explorer Programme, Magnetopheric Multiscale Satellites (MMS) and the Global Precipitation Measurement Core Observatory (GPMM).

What has happened with these projects during these two years?


Understanding the Water Cycle and Improve the Models

Global Precipitation Measurement Core Observatory


GPMM near ready for launch. Credit: NASA/Michael Starobin



Water is the main reason for all types of life on Earth and knowledge about the water cycle is extremely important. NASA and the corresponding Japanese organisation JAXA are the main contributors to a satellite that will detect the water distribution in the atmosphere to better the understanding of the water cycle.

When we visited the NASA Goddard Spaceflight Center, Maryland early summer 2012, one of the large projects that was being carried out in the institute’s clean room was the Global Precipitation Measurement Core Observatory. Now, nearly two years later, the laboratory is launched and the first pictures received.

The GPM mission concept builds on the Tropical Rainfall Measuring Mission (TRMM) launched in 1997 and as measured precipitation over tropical and subtropical regions between 35 degree north and south. GPM will cover the areas between 65 degree, corresponding to all main land in south and in north, to the southern part of the Nordics, Alaska, Canada and Russia.

As the name indicates, the satellite is only a part of a large system of current and further missions, where Europe will contribute with data from the polar orbiting Metop satellite.  The GPM constellation, which consists of nine different satellites, will provide measurements on the:

– Intensity and variability precipitation;

– Three-dimensional structure of cloud and storm system;

– Microphysics of the ice and liquid particles within clouds; and

– Amount of water falling to Earth surface.

The sensitivity for the instruments is very high. Rainfall down to 0.2 mm/hour can be detected. Observations from the GPM constellation, where the GPM Core Mission plays a key role, will improve the models for weather and climate models. In addition, the satellite will also better the forecast of hurricanes, landslides, floods and droughts.


Investigates How the Sun’s and Earth’s Magnetic Fields Connect and Disconnect

NASA’s Magnetopheric Multiscale Satellites

mms stacked

All four satellites stacked for the vibration test. Image Credit: NASA/Barbara Lambert

Goddard Space Flight Center in Maryland, USA, early 2012, four new satellites were in the early assembling phase in one of the assembling halls. Now, near two years later, the engineers have finalized the work, and the four Magnetopheric Multiscale satellites are assembled in a complete stack ready for vibration tests, tests that shall prove that the four satellites can bear the forces the launch entails.

The vibration tests determine whether the four MMS spacecrafts can withstand the extreme vibration and dynamic loads they will experience inside the fairing of the Atlas V launch vehicle on launch day. It’s during the first moments after lift-off that the spacecraft is exposed to the most stress.


The early assembling phase. The first satellite has found its form.
Credit: Nordicspace/Baard Kringen


The Mission

The MMS mission consists of four spacecrafts outfitted with identical instruments. The mission will fly through near-Earth space to study how the Sun and Earth’s magnetic fields connect and disconnect, something which is an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and occurs throughout all space.

MMS is a Solar Terrestrial Probes Program, or STP, mission within NASA’s Heliophysics Division. STP program missions improve our understanding of fundamental physical processes in the space environment from the sun to Earth, to other planets, and to the extremes of the solar system boundary.

The four identically instrumented MMS spacecrafts fly in an adjustable pyramid-like formation that enables them to observe the three-dimensional structure of magnetic reconnection. This enables them to determine whether reconnection occurs in an isolated locale, everywhere within a larger region at once, or travelling across space. MMS sensors will measure charged particle velocities, as well as electric and magnetic fields, with unprecedented (milliseconds) time resolution and accuracy needed to capture the elusively thin and fast-moving electron diffusion region. MMS probes reconnection of solar and terrestrial magnetic fields in the dayside and night-side of Earth’s magnetosphere, the only natural laboratory where it can be directly observed by spacecraft.

For more about the MMS mission, visit: www.nasa.gov/mms



Explorer Missions – Effective Way to Knowledge


Model of the Explorer 1 at Jet Propulsion Laboratory, Pasadena, California Credit: Nordicspace/Baard Kringen

When NASA launches the Astro-H satellite around the turn of this year it will be a new mission in the world’s longest running satellite programs – the “Explorer program”.

Over the years, since the firs
t American satellite in space, Explorer 1, NASA has launched a series of “Explorer” spacecrafts carrying a wide variety of scientific investigations. The list identifies more than 90 successful and very few unsuccessful missions until now – and more will follow.

A Long-lived Series of Long-lived Spacecrafts

NASA’s Explorer spacecraft series is not simply the longest running series of spacecraft, it has produced highly-durable (i.e., well-engineered) spacecrafts as well. Of the successful Explorer missions, five of them had had missions which lasted 10 or more years, the longest of which (IMP 8) has been operational for nearly three decades and produced valuable information about the solar wind, and the IUE spacecraft operated for near two decades and produced data for the astronomical community.

The Explorer program is designed to provide frequent, low-cost access to space for principal  investigator led space science investigations relevant to the heliophysics and astrophysics programs in NASA’s Science Mission Directorate.

The Explorer program has launched more than 90 missions since 1958, including Explorer 1, which discovered the Earth’s radiation belts (Van Allen Belts), and the Nobel Prize enabling mission Cosmic Background Explorer (COBE) mission.

The program is managed by NA
SA’s Goddard Space Flight Center in Maryland for the Science Mission Directorate. https://explorers.gsfc.nasa.gov

Fifty Six Years and Still Running

The Explorer program is not a historic program, but still running and very vigorous. Today, there are two Explorer (EX) missions in the developing phase with launch in the 2016-2017 time frame. In addition, NASA participates in three Missions of Opportunity (MO), the first with launch around the first turn of the year, while the last two in the same time frame as the EX missions.

The running projects are the EX missions ICON and TESS and the MO missions Astro-H, GOLD and NICER.

The two EX projects were selected from proposals submitted in response to the NASA Explorer announcement in 2010. The proposals were judged to offer the best science value among the six concept studies submitted to NASA in 2012.

The Celebrated Explorer Program.

Explorer satellites have made impressive discoveries: Earth’s magnetosphere and the shape of its gravity field; the solar wind; properties of micrometeoroids raining down on the earth; much about ultraviolet, cosmic, and X-rays from the solar system and universe beyond; ionospheric physics; solar plasma; energetic particles; and atmospheric physics. These missions have also investigated air density, radio astronomy, geodesy, and gamma ray astronomy. Some Explorer spacecraft have even traveled to other planets, and some have monitored the Sun.


The Explorer Class

Today the Explorer missions are defined in different classes, mainly based on the maximum cost for NASA.

Medium-Class Explorers (MIDEX)

Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $180 million total cost to NASA.

Explorer (EX)

Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $200 million each (fiscal year 2011 dollars), excluding the launch vehicle.

Small Explorers (SMEX)

Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $120 million total cost to NASA.

University-Class Explorers (UNEX)

Investigations characterized by definition, development, launch service, and mission operations and data analysis costs not to exceed $15.0M (real year dollars) total cost to NASA. UNEX missions will be launched by a variety of low cost methods.

Missions of Opportunity (MO)

Investigations characterized by being part of a non-NASA space mission of any size and having a total NASA cost of under $55 million. These missions are conducted on a no-exchange-of-funds basis with the organization sponsoring the mission.