Mission Elapsed Time:
Beginning 1/19/06 19:00:00 UTC
2911 Days (7.96 yrs.) 08 Hours 23 Minutes
Pluto Closest Encounter
4/12/15 00:00:00 UTC
457 Days (1.25 yrs.) 20 Hours 36 Minutes
Pluto Closest Approach:
7/14/15 11:49:59: UTC
551 Days (1.51 yrs.) 08 Hours 25 Minutes
With Pluto encounter operations now just a year away, the New Horizons team has brought the spacecraft out of hibernation for the first of several activities planned for 2014. Mission operators at the Johns Hopkins Applied Physics Lab in Laurel, Md., “woke” New Horizons on Jan. 5. Over the next two weeks the team will test the spacecraft’s antenna and repoint it toward Earth; upload commands into the onboard Guidance and Control and Command and Data Handling systems, including a check on the backup inertial measurement unit and update of the spacecraft’s navigational star charts; and conduct some navigational tracking, among other routine maintenance duties. “We’ve had busier wakeup periods, but with long-distance Pluto encounter operations starting only a year from now, every activity is important,” says APL’s Alice Bowman, New Horizons mission operations manager.
The pace of operations picks up significantly later this year. In late June the team will wake New Horizons for two and a half months of work, including optical-navigation (“homing”) activities using the Long-Range Reconnaissance Imager (LORRI) to refine the probe’s course to Pluto. The team will also check out the spacecraft’s backup systems and science instruments; carry out a small course correction to trim up New Horizons’ approach trajectory and closest-approach timing at Pluto; and gather some science data by measuring the variations in Pluto’s and Charon’s brightness as they rotate.
New Horizons Position in 2 Dimensions:
New Horizons: Solar System Distances:
New Horizons is placed back into electronic slumber on Aug. 29, a “rest” that lasts only until Dec. 7. “From there it will stay awake for two years of Pluto encounter preparations, operations and data downlinks,” Bowman says. Distant-encounter operations begin Jan. 12, 2015.
“The future has finally arrived,” says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colo. “After all the time and miles in the rearview mirror, the turning of the calendar page last week to 2014 means we'll be exploring the Pluto system next year!”
The Student Dust Counter (SDC) flies aboard the New Horizons mission, a NASA mission to Pluto and the Kuiper Belt. A dust counter is an instrument that counts particles of dust in space; the SDC collects this information when grains of dust hit the instrument as it travels to Pluto. The SDC will travel out into the solar system 40 times the distance from the Earth to the sun, or 40 astronomical units. The record-holding dust counter, on Pioneer, only measured dust to about 18 astronomical units. As it travels to Pluto and beyond, SDC will provide information on the dust that strikes the spacecraft during its fourteen-year journey across the solar system. These observations will advance our understanding of the origin and evolution of our own solar system, as well as helping scientists study planet formation in dust disks around other stars.
Student Dust Counter
Compared to previous, similarly designed dust counters, the SDC is lighter—only 1.6 kilograms (3.5 pounds)—uses less power, and was much less expensive to develop. Stringent constraints on mass, power, and budget are part of any planetary or space mission; these characteristics help make SDC an attractive dust instrument for future missions. The SDC has a set of detectors, about the size of an 18 x 12-inch cake pan, which detect incoming particles. The detectors are made of a plastic film called Polyvinylidine Fluoride (PVDF). The detectors are all mounted to a large piece of honeycombed aluminum, which is then bolted with aluminum feet to the New Horizons spacecraft.
A computer simulation of the density of dust throughout the solar system.
The Student Dust Counter has three main goals:
1) To map dust distribution and density. Dust is not spread evenly throughout space; it varies in density throughout the solar system.
2) To help scientists understand variation in where different-sized particles are located in the solar system.
3) To determine how fast the Kuiper Belt produces dust. The small, icy bodies in the Kuiper Belt are constantly colliding and causing little bits of each other to chip off. Through additional collisions over time, these chips are ground to dust; scientists want to understand how quickly this process happens.
The New Horizons spacecraft has a high-gain antenna that transmits scientific data about dust back to Earth as radio waves. Moving at the speed of light, it still takes the data hours to arrive at Earth. For example, from Pluto, the data will take four hours to arrive at the NASA Deep Space Network here on Earth. The Network receives the data and sends it out to the New Horizons team.
The high-gain antenna on the New Horizons spacecraft
Comparing with past mission data:
Scientists have already completed initial comparisons SDC data to existing data. The first results, published in Geophysical Research Letters, indicate that SDC measurements of dust inside 5 astronomical units agree well with the earlier measurements made by the Galileo and Ulysses missions.
Scientists will not be comparing SDC data on dust further out than 18 astronomical units to other missions because such data doesn't exist. Instead, scientists will be testing their theoretical understanding of dust in the solar system, adjusting their theories to accommodate the new data.
Improving computer simulations:
Scientists will also compare the SDC data retrieved to several computer simulations of expected dust distribution and density. Computer models of the dynamics of Kuiper-Belt dust grains show that dust tends to get trapped near Neptune in sync with the planet's orbit. SDC will take data in this region so that scientists can improve their computer models with real data.
Each time a dust particle hits a detector, the electronics store five pieces of data:
1. Detector number that the dust particle hit
2. Minimum sensitivity of the detector
3. Size of the electronic pulse generated, which is turned into the particle size using ground calibrations
4. Time of impact
5. Time of day the data was streamed to Earth
A visualization of data generated from the SDC.
After scientists receive all the data from the SDC and ensure that the instrument has worked properly, the next step is to analyze the data. Data analysis can be difficult. If the data differs greatly from what scientists were expecting to find, they have to decide whether their instrument was wrong, or whether their theories were wrong. If the data is what was expected, scientists have to make sure they've analyzed it correctly so no bias occurs. If scientists come to the conclusion that their data are valid and good, then they determine what new information they have gained.
A team of 20 students from the University of Colorado have collaborated, designed, and built the SDC for the New Horizons Mission.