86

The high gain antenna of New Horizon as an opening angle of its beam of about 0.6°. That means, it has to be pointed at Earth with an error margin of 0.3°. As a practical example, this is more like pointing a torch (flashlight) with a (well focused) beam at a far target than aiming with a tiny Laser spot. For comparison, 0.6° is slightly larger than the ...


78

New Horizons will never overtake Voyager 1. Although New Horizons is currently faster than any other man-made object, it won't be by the time it reaches the outer corners of the solar system. From the John Hopkins University/Applied Physics Laboratory New Horizons page: Though New Horizons will also reach 100 AU, it will never pass Voyager 1, because ...


59

I think a lot of folks see these gorgeous photos of distant galaxies, with fine detail on dust lanes and spiral arms and assume that since they’re so far away, seeing Pluto would be easy. But while these galaxies are far away, they’re also huge. The (relative) detail that can be seen in any given telescope will be found by the object’s size divided by the ...


46

Here's a nice graph of Voyager 2's speed, and the difference made by the gravitational assists: You can see that the probe slowed down between assists. New Horizons would follow a similar graph, but with fewer assists its speed will end up below Voyager 2's, as @gerrit said.


40

Distance. Size of the target. Its poor albedo at such distance to its only source of illumination, the Sun, compared to closer celestial bodies. And movement of the target and the vantage point in their orbits preventing advanced image interpolation techniques combining multiple observations of same side of Pluto at same lighting conditions. Pluto is ...


38

New Horizons was hidden behind the Sun a few days after the flyby, from January 4th to January 7th. Almost as soon as the encounter and earliest downlinks are over, New Horizons will go into solar conjunction from January 4 to 7. I asked Alice Bowman what implications that has for the mission, and she replied: "During solar conjunction, the downlink data ...


33

This mission study came up with a 900 kg nuclear-electric-propulsion spacecraft launched on an Ariane V with a C3 of 100 and a Jupiter gravity assist along the way. 1.05 kW electrical power at Pluto from RTGs is required. That would be four "classic" NASA RTGs, or about nine MMRTGs. It has a 20 kg science payload. (New Horizons has ~30 kg of instruments, ...


32

The long distance to the Sun mandates long exposure times. The New Horizons spacecraft needs to be relatively stable and its pointing accurate throughout these long exposure times. New Horizons does not have a scan platform. The cameras and other science instruments are fixed with respect to the vehicle. The satellite has to turn as a whole to keep the its ...


28

Space is basically a vacuum, so there's no air resistance. A probe that's been launched will travel at the same speed indefinitely. Because New Horizons is moving away from the Sun, it loses some speed to overcome the Sun's gravity. New Horizons was launched on the fastest rocket they could get. Then it used a gravity assist from Jupiter to gain some more ...


27

There's no point in having a live stream, because we won't receive encounter data in real time. On the 14th, New Horizons will be busy aiming its instruments at Pluto. Due to the design of the spacecraft, it can't do that and transmit information at the same time. The cameras and antenna are all fixed in place, so they have to rotate the entire spacecraft to ...


27

In addition to the limited downlink time due to it being hidden behind the Sun, it should be noted that the New Horizons team is prioritizing downlinking the metadata of each of the images. This will allow them to prioritize downloading the images that actually have something interesting in them, and deprioritize the images that will be of blank space. Keep ...


25

Organic Marble is correct in the comment, New Horizons is now busy with Departure Phase (DP2 from Aug 5-Oct 22) science and transmitting plasma and dust data, and no additional images will be transmitted until September 14 when Science Data Playback phase starts. All images from New Horizons Press Conferences Materials: Image sources: (1): Alan Stern, New ...


24

Look up the inverse square law. With the same power available at the spacecraft, the signal strength received at Earth diminishes as the square of the distance. If the vehicle is solar powered, then it is possible that it will also reduce the transmitted power as it goes farther from the Sun. However it is more likely to reduce the transmission duration ...


23

New Horizons pans during shots to eliminate motion smear. See this related question. The Voyager mission proved that this was possible: Between Voyager 2’s encounter with Saturn in 1981 and Uranus in 1986, controllers developed a technique called “image motion compensation.” This involved moving the scan platform at slow rates, which was found to be ...


23

It was said in here that the time to reach Pluto was shortened by 3 years. It's also said that after the Jupiter flyby the probe gained ~ 4 km/s accelerating to the speed of 23 km/s relative to the Sun. We can use simple Keplerian estimate (ignoring all complexities of the actual orbital mechanics) to obtain the speed when the probe approaches Pluto, \begin{...


22

Propulsion Until someone solves the N-body problem every spacecraft needs some kind of propulsion to correct its course during the mission. New Horizons uses a Hydrazine based propulsion system including four 4.4 N main thrusters and twelve 0.9 N attitude control thrusters. Its 77 kg fuel tank allows a total post launch delta-v of somewhere over 290 m/s (...


22

Modern technology doesn't change the major constraints of rocket propulsion significantly. In the absence of a gravity assist, the most fuel-efficient route from Earth to Pluto is approximately a 45-year journey. Bringing that down to 9 years already represents a large investment in propulsion fuel; New Horizons set the record for the highest launch speed ...


22

For getting really high resolution stuff, you need to get outside of the atmosphere. The best instrument to do this is the Hubble Space Telescope. The resolution of Hubble is about 0.05 arc seconds. Pluto is currently around 3.5 billion miles. That gives a resolution of 850 miles or so. This is limited by the size of the mirror that Hubble has, which is ...


21

A bit of good old Google-fu reveals this blog post by Emily Lakdawalla for when New Horizon's LORRI imagery of Pluto is expected to be of better resolution than that of Hubble Space Telescope's Wide Field Camera 3 (WFC3) (relevant excerpts only, no copyright infringement intended): So New Horizons' vision is is about 25 times less sharp than Hubble's. ...


21

Edit as of August 31, 2015: Looks like 2014 MU69 will be the post Pluto target. Paul Gilster has a nice article on Centauri Dreams. Edit as of Jan. 3, 2015: This article says 3 potential candidates were found in December of 2014. This article says the New Horizons team is running out of time to find KBOs to check out after it passes Pluto. No post Pluto ...


21

New Horizons also uses very strong error correction coding. Specifically, rate 1/6 turbo coding and BPSK (binary phase shift keying). This expands the signal bandwidth by a factor of six, but it still reduces the required energy per user data bit. This allows a higher data rate for a given transmitter power. The minimum Eb/N0 for this code is about 0 ...


20

Per New Horizons science team member John Spencer, via Emily Lakdawalla, the spacecraft is not yet close enough to fully resolve the the shapes of Pluto and Charon. Their apparent shape is dominated by the camera / telescope's point spread function, which is "slightly teardrop shaped, giving that gibbous appearance".


20

This is probably the easiest to answer if we take the same mission profile and just track from the Pluto flyby backwards. I'll make some rather broad assumptions and first order approximations, like that NASA had their NEXT ion thruster developed to the highest technology readiness level (they did exist when New Horizons launched, but not at TRL required to ...


20

New Horizons was designed to do a fly-by of Pluto in a relatively large distance. It was only in range of Pluto for a couple of hours. Dawn is designed to orbit Ceres at much closer range. To accomplish its mission, New Horizons had to have such a high resolution camera to get the desired results. Instruments are designed specifically for a certain mission. ...


19

The “Sailboat Island” gets its name from a Poincaré Surface-of-Section (SOS) plot of potentially stable S-type family of orbits in the Pluto-Charon system. From NASA Ames' blog post titled Playing Marbles at Pluto. Looking at the Dynamic Dust Environment. Generators, Sweepers, and Sweet-Spots by Kimberly Ennico: Othon Winter (UNESP Brazil) spoke about “On ...


18

I am guessing VxWorks but I haven't found any sources to validate this. Close, but no cigar. If New Horizons flight software was built by Jet Propulsion Laboratory (JPL), then I guess Wind River's VxWorks RTOS would have been their first choice (it's also a popular choice for hardware on Mars - Pathfinder, Sojourner, Phoenix lander, Spirit, Opportunity, ...


18

Short answer Yes, what you see in the news are recent images. It takes about 1 hour to the probe to send one image bit by bit, and about 4 hours for the bits to travel from the probe to Earth. If New Horizons could do the scientific work, take images, and send them at the same time, this would be great, but that's not the case. While the probe had more ...


17

TL;DR: Data rate is directly related to effective noise floor, which is related to bandwidth and received power (and lack of interference). Lower received power means increasing transmit power or reducing bandwidth (speed). APL had to choose the latter due to constraints. Read on for a much more detailed and long-winded explanation (sorry if too long ...


16

It's just a coincidence, and officially, the dates aren't that close. The IAU (International Astronomical Union) General Assembly in Prague, Czech Republic where the new definition of a planet was endorsed and with it Pluto losing its planetary status, happened in late August, 2006. Final draft that was voted on states: A planet is a celestial body that ...


16

The official trigger for what caused Pluto's demotion as a planet was the discovery of Eris, in October 2005. For a number of years, starting with the discovery of non-Pluto Kuiper Belt Objects (KBOs), and later with the discovery of other large objects in the Kuiper Belt. When Eris was discovered, the IAU decided that it needed to decide what a planet was. ...


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