New Horizons Flies by Uranus

The Pluto-bound New Horizons spacecraft will fly by another planet today (March 18, 2011). However, the robotic craft won’t be taking any images as it zooms past Uranus’ orbit at about 6 p.m. EDT, 3.8 billion kilometers (2.4 billion miles) away from the gas giant (and 2.0 billion km (1.8 billion miles) from Earth). New Horizons is currently in hibernation mode, and the great distance from Uranus means any observations wouldn’t provide much as far as data and images. But, even so, this event is a ‘landmark’ so to speak in New Horizon’s gauntlet across the solar system.

“New Horizons is all about delayed gratification, and our 9 1/2-year cruise to the Pluto system illustrates that,” said Principal Investigator Alan Stern, of the Southwest Research Institute. “Crossing the orbit of Uranus is another milepost along our long journey to the very frontier of exploration.”


New Horizons is now well over halfway through its journey to Pluto. Motoring along at 57,900 km/hr (36,000 mph), it will travel more than 4.8 billion km (3 billion miles) to fly past Pluto and its moons Nix, Hydra and Charon in July 2015.

But the journey doesn’t end there. After that, New Horizons will head off to a post-Pluto encounter with other objects within the Kuiper Belt, some event(s) which might take place even into the 2020’s. The planetary science community is working on the selection of potential targets.

The mission still has more than 4 years to go to get to Pluto; it will take 9 nine months to send all the data back to Earth.

The next planetary milestone for New Horizons will be the orbit of Neptune, which it crosses on Aug. 25, 2014, exactly 25 years after Voyager 2 made its historic exploration of that giant planet.

“This mission is a marathon,” says Project Manager Glen Fountain, of the Johns Hopkins University Applied Physics Laboratory. “The New Horizons team has been focused on keeping the spacecraft on course and preparing for Pluto. So far, so good, and we are working to keep it that way.”

Source: New Horizons

25 Replies to “New Horizons Flies by Uranus”

  1. “Hee hee, he said Ur… planet!” For Pluto, I think the narrator meant _dwarf_ planet.

    1. You noticed that too. I got in here to make a bit of light about that. I suppose if you are sending a spacecraft to Pluto it must be a planet!


    2. When New Horizons was conceived and developed, Pluto WAS a planet. And the categories “dwarf planet” and “planet” are likely to be revised again as more objects are discovered.

      It doesn’t really matter anyway – I think we should just call them all planetoids and leave the semantics to the IAU.

  2. A better title would be “New Horizons flies past the orbit of Uranus”. It was actually closer to Uranus earlier in its flight.

    1. Ha! Ain’t Serendipity just beautiful. Similar thoughts at same time on different parts of the planet!

  3. Shouldn’t it be more properly entitled… “New Horizons Flies Through Uranus’ Orbit “ ?

  4. I’m just wondering: When will NewHorizon overtake the Voyager probes? And will it be able to send data when it crosses the outer boundaries of the solar system? And for how long?
    (I’m just too lazy to search for myself. So, if anyone has answers or a link, he/she is kindly asked to provide them. 😉 )

    1. Tay… this article states that New Horizons is traveling at 36,000 mph. Voyager I is traveling at roughly (although slowing) 35,000 mph while Voyager II is traveling at 39,000 mph. Two calculations! Lessee here.. if New Horizon’s is catching up to the Voyager I 1,000 miles every hour and Voyager I is roughly 9 billion miles away, then it would take 9,000,000 hours or 375,000 days or 1,027 years to catch up!

      1. Since you like “calculations!” [I do too, not just in the mornings] I’m just going to point out that of course Wp has it right and that you haven’t figured in gravity. By the time that NH is at the same distance to the Sun as VI, it will have slowed as per the given figures. No catch up.

    2. I wondered this as well and looked it up a little while ago. Here’s what Wikipedia says:

      “Even though it was launched far faster than any outward probe before it, New Horizons will never overtake Voyager 1 as the most distant man-made object from Earth. Close fly-bys of Saturn and Titan gave Voyager 1 a massive advantage with its extra gravity assist. When New Horizons reaches the distance of 100 AU, it will be travelling at about 13 km/s, around 4 km/s slower than Voyager 1 at that distance.”

  5. Okay, so New Horrizions hit a speed of nearly 60,000 miles per hour after main engine shutdown when it was launched.
    My question is this…Is this the maximum possible speed we can get out of a space craft with current technology?
    I’m just wondering, (and supposing costs was no object with the goal of the fastest speed possible for a probe like N.H.) what if it were possible to have placed that whole Atlas 5 on top of a Delta 4 Heavy with 4 of those two stage side boosters instead of the 2 that Delta heavy’s use, and if the SRBs on the Atlas 5 were like the ones used for the shuttle.
    What kind of possible speed (in theory of coarse) could such a configuration achieve?

    Then suppose we had the absolute best senero for gravity assists from the Moon, Mars, and the gas giants. How much more could that add? and how much shorter would the whole trip theroritacally be?

    Just curious about what could be done under the most idea conditions.

    1. Unfortunately it is morning here, so I have to cheat and likely make an erroneous claim from a rough overview:

      V1 and V2 are Sun escaping, IIRC. Most of the Sun escape velocity needed at Jupiter distance (~ 18.5 km/s) is supplied by Jupiter gravity assist (delta-v to Sun max 2*v_Jup or 26 km/s). So that is pretty much that they needed to design for.

      Tor turn it around, those are the fastest interplanetary objects we have made. So that is likely pretty much it.

      1. Dammit! “Tor turn it around” – To turn et cetera.
        Also: Planetwatcher, I realize my comment isn’t much helpful, so I hope someone will make the effort to go through “best mission profiles” to eke out the max of “planetary billiard” possibilities.

    2. The spacecraft did not launch at 60,000mph, or nearly 100,000km/hr, or 27.8km/sec. The fastest launch terminal speed from our rockets is about 17km/sec. Such spacecraft are aimed at Jupiter which passes by the planet. Some of the orbital energy of Jupiter is transferred to the spacecraft which kicks it further out into the solar system. This is a gravitational billiards game, where the spacecraft picks up a delta vee (change in velocity) that takes it further out.

      To get a spacecraft to the sun means putting the craft at a dead stop in heliocentric coordinates so the craft would drop into the sun by its gravity. The Earth orbits the sun at 29.5 km/sec, which is the velocity required of such a spacecraft. This is one reason why launching our garbage to the sun is problematic. So getting close to the sun is energetically difficult. The MESSENGER craft which is now in orbit around Mercury did a number of gravitational boosts from Venus and Earth in a complicated orbit over 7 years in order to reach Mercury.


    3. That might be a Delta V? That is to say… a Delta IV with four strap on boosters(?) and a Centaur/VASIMR combination upper stage? I guess we’ll have to wait for the VASIMR engine to come on line to fully answer that “…maximum possible speed we can get out of a space craft?” question?

      1. Delta vee means change in velocity. The fastest we can currently get something, which I was wrong on above, is about 20km/sec.


      2. Now VASIMR would be the ticket. Especially if combined with solar sails. But I don’t see much likelyhood of VASIMR ever getting built any time soon.
        Perhaps solar sail/ion drive combination is what we can realisticly expect to see happen

  6. Thank you Lawrence. If I figured it correctly, then that means the best possible time to Pluto with current technology would be around 8.2 years. Not a whole lot less then what NH is doing.
    I sort of hoped that much bigger and more powerful rockets burning for a longer period of time would have made more of a difference.. Especially making a less timely trip to Jupiter, and perhaps geting a bigger gravity boost because of greater speed, but it sounds like it just doesn’t work that way.

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