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Reviews > Packs > Internal and External Framed Backpacks > Osprey Packs Atmos 35 > Test Report by Andrew Buskov

Osprey Atmos 35 FrontOsprey Atmos 35
Osprey's redesigned light and fast series pack for true backcountry adventure.
Andrew Buskov
Initial Report: September 25, 2009
Field Report: November 30, 2009
Long Term Report: January 26, 2010

Tester Biographical Information

Name: Andrew Buskov
Age: 34
Gender: Male
Height: 5 ft 9 in (1.75 m)
Weight: 223 lbs (101 kg)

44 in (112 cm)

Waist: 38 in (97 cm)
Torso Size: 21 in (53 cm)
Email: Rescue(at)Corridor9(dot)net
City, State Zip Madisonville, Kentucky  USA

Backpacking Background:

I’ve been backpacking for years now, and have slowly started developing my ideal style. I’ve gotten my pack weight down to roughly 25 – 30 lbs before water, and am whittling it down every hike. Day hiking is nice, but getting out over multiple nights is really what I enjoy. I like to take my time and enjoy the scenery as opposed to hiking hard. I also like being comfortable and insist on an air mattress. I usually tent or hammock, but stay in shelters when needed.

Osprey BackProduct Information:

Item: Osprey Atmos 35
Manufacturer: Osprey
Year of Manufacture: 2009
Listed Weight: 3 lbs 0 oz (1.36 kg)
Actual Weight: 3 lbs 0 oz (1.36 kg)
Color: Aspen Gold
Additional Colors: Green Apple, Graphite Grey

Product Overview:

Osprey redesigned the Atmos 35 for the 2009 hiking season. Starting with their spacious interior ranging from 1900 - 2300 cu in (32 - 38 L), and a manufacturer recommended usable load range between 25 - 35 lbs (11 -16 kg), the new packs include refined  improvements including a LightWire alloy frame with breathable tensioned mesh back panel for superior ventilation, multiple options for hydration setup, and even the much raved about inside/out compression system With three color options, three sizing options, and even a women's specific model  (Aura), the Osprey Atmos 35 really does appear to be the all around light and fast backcountry pack. 

Initial Impression:

Mesh CompartmentThe Osprey Atmos 35 (herein referred to as the Atmos or pack) arrived to my door intact, with all equipment, and with no signs of damage or poor workmanship. Upon opening the packaging, I glanced over the pack with a renewed sense of  excitement toward the upcoming hiking season. I took special interest in some of the new features that I hadn't seen on other packs, and found some nice design changes from the last Osprey pack I tested.

Starting from the top I found the single main compartment to be roomy and easy to access. The dual zippers run halfway down both sides allowing a majority of the interior compartment to be accessed. Because of the long zippers, it's considered a panel loading style pack, versus a top loading pack that just has an opening at the top. There is no sleeping bag compartment and, other than this main zipper, no other way of  accessing the interior main compartment of the pack. However, during initial packing of the Atmos 35, I found it easy to access all items that I packed without much problem. Even the items that were placed at the bottom of the pack were easily reachable from the main zipper. Because of the dual zipper configuration, I was also able to over stuff the main compartment and still reach items without everything falling out due to the ability to shift the zippers to either side of the pack. The ability to reach items without losing gear all over the ground is definitely a plus over some of the other panel loading packs I've used.

Pocket Configuration
In addition to the main compartment, there are 7 more exterior compartments or pockets located in different places on the Atmos 35. Four of these compartments are zippered while the remaining three are more pouch type than anything. At the top of the pack, closest to the back frame is a rather large, single zipped, mesh compartment with enough space to easily fit two standard size wide mouth Nalgene bottles along with various other small items. Attached to the mesh panel is Osprey's standard key ring holder. Further down the front side of the pack is another large, double zipped, exterior pocket roughly the same size as the mesh one listed above. Entry into this pocket was a bit tighter due to the smaller entry point, but I was still able to stuff two wide mouthed Nalgene bottles into this compartment as well. The additional two zippered pockets are made of mesh and located on each side of the hip belt. Both are fairly large and sewn in such a fashion so that their contents will not be crushed while wearing the pack. They will both easily accommodate a camera, small GPS unit, various snacks, and compass while still having room for additional items if necessary.

AirSpeed CavityThe large stretch panel covering the front and found on a majority of Osprey packs is easily big enough to hold a pair of camp shoes, running shoes, entrenching tool, or rain gear if necessary. It is secured near the top by a quick clip that is fairly easy to operate. There is a mesh oval located in the center of the panel, and a small mesh semi-circle located at the bottom of the panel for drainage. Both have welded seams and feel very secure. There are also two pockets on the sides of the pack for water bottles or various other items. Both of these pockets have a mesh fabric sewn into the bottom to facilitate drainage. In addition, they are designed in such a way as to allow the bottle to sit in the traditional upright position, or the new more accessible diagonal position as seen in the pictures above. Also incorporated is the new Inside/Out compression system. This allows the me to decide how I want the compression straps run. On older packs, the compression straps were on the outside of these pockets. This made it rather difficult to access bottles or other equipment without loosening the straps. With the new system, I have the ability to run the compression straps along the inside of the pocket, thus giving me the ability to reach my bottle without loosening the compression straps. This also means a reduced chance for the interior load of the pack to shift every time I need a drink; a much desired feature indeed.

Hydration CavityThe LightWire alloy frame and stretched mesh backing of the Atmos creates a spacious ventilation cavity that covers the entire back of the wearer. This AirSpeed cavity is made of a mesh material with half-moon shapes along the sides to greatly improve air movement. While it's made of mesh, it's rather rigid and feels very comfortable. Because of this design, the ability to vary the pack size is gone. Thus the importance of correctly sizing the pack prior to purchase becomes all the more important.

The hydration setup, seen on the left, is quite intriguing. Starting with the standard setup, the interior compartment of the pack includes a fairly sizable pocket for a variety of hydration bladders. There is a mini quick clip located at the top of the pack to allow me the ability to hang my bladder so that it doesn't slide down to the bottom of the pouch. However, there is an additional method that allows me to hang the bladder in the AirSpeed cavity. While the manufacturer states that this method may not work for all models of hydration bladders, it does appear to be a useful feature. Not only does hanging the bladder in the AirSpeed cavity give me additional room in the main compartment, but I also see the ability to use this method as an active cooling/heating system during extreme temperatures. Because the bladder sits right against the mesh, and therefore against my back, the ability to have hot or cold water against my back may prove to be useful. This will have to be weighed against the loss in ventilation though.

Pockets, Straps, Poles
Additional bells and whistles include the Stow On The Go attachment system which allows me to attach my trekking poles to the bottom of the pack and shoulder harness without stopping. This is a feature I've used on my other Osprey pack and it really does save time and function well during periods where the ability to use trekking poles changes often due to terrain. Also included is an adjustable chest strap with integrated whistle. A nice feature seen all over the pack is the new design of the zipper pulls; they are rounded allowing them to be easily grasped even with the thickest gloves on. This is wonderful as I prefer hiking in the winter and hate taking off my gloves to get into my pack.

Zipper DiseaseThere are a couple of things that I'm concerned about or feel could be changed just from my initial observations of the Atmos 35. During my initial packing of the Atmos I closed the zipper in such a way as to create 4 instances of zipper disease within a 6 in span. While I understand that I may not have been as careful as I could have, this still concerns me as I don't feel the zipper was subject to enough strain to cause this. One thing I don't want in a pack is the need to be gentle with it. I feel it should stand up to some light abuse and still remain functional. Another quirk that really bothers me is the adjustable chest strap. While this is a wonderful design in theory, the ability to easily remove and replace the chest strap is missing. The molded plastic connectors ride snugly up and down over a plastic insert inside the shoulder strap. Because they are so snug, removing them is difficult. However, I have found that replacing them back on the shoulder strap to be extremely difficult. I wish there was a way to more easily remove these straps as I often like to go without a chest strap depending on the weight my load.

In all, the Osprey Atmos 35 appears to be a well thought out, very well designed pack for the light and fast crowd that still craves breathability along with some of the bells and whistles found on larger packs.

I'd like to thank and Osprey for allowing me to participate in this test.

Field Report: November 30, 2009

Field Conditions:

I was able to use this pack a total of four occasions within this testing phase. A multiple night session in Rocky Mountain National park served as the first test. Temperatures during the outing ranged from 70's (21 C) during the day to below freezing (-0 C) during the night and at an elevation around 9000 - 10,000 ft (2750 - 3050 m) throughout the trip. I was also able to use this on a couple of day hikes in the Western Kentucky area. The temperature for the outings ranged from 50 - 65 F (10 - 18 C) over the period of 3 different days. Elevation here is roughly 400 ft (120 m) with little change in terrain as opposed to RMNP.


As I was able to use this pack on both multi-night hikes and day hikes, I was able to get a better feel for the range of use that the Osprey Atmos 35 provides. Starting off with a multi-night trip to Rocky Mountain National Park I was able to fit a wide variety of gear inside the pack. Because I needed more gear due to the vast weather changes I was to expect at various altitudes, I found that I quickly ran out of usable space in the main compartment. Let me begin by listing the gear that I was able to take:

  • 15 F (-9 C) Big Agnes Lost Ranger sleeping bag
  • Outdoor Research Hydroseal DryComp AirX compression sack
  • Exped SynMat Lt 7 air mattress
  • Hennessy Explorer Ultralite A-Sym
  • MSR MicroWorks water filter
  • Montbell UL Thermawrap Parka
  • Jetboil PCS Stove
  • Thermal Underwear
  • 2 L CamelBak Insulated StoAway
  • 50 ft (15 m) rope bag for hanging food
  • Map, Compass, and Rite in the Rain Outdoor Journal
  • Navigational Guide
  • Toiletries
  • Food Cozy & Thermal Seat Pad
  • Petzl Tikka Plus Headlamp, Extra Batteries
  • Various medical supplies
  • 3 days food & cooking supplies
  • Rain cover
  • 2 changes of clothing (socks, undies, pants, shirts)
  • Other miscellaneous items (keys, brochures, etc.)

While I was able to cram all of the above gear into my pack, finding and shuffling gear inside the stuffed pack proved to be a major problem. I initially thought that having a large front opening would prove a better option for finding gear at the bottom of my pack. However, I found the opposite to be true. So many times I dumped almost the entire pack contents on the ground due to trying to find something near the bottom. It was as if my pack was vomiting its contents all over the place. I eventually got fed up and decided not to dig around in my pack unless it was absolutely necessary. This is not how I want my trips to go. I prefer comfort and will only sacrifice if absolutely necessary.

That being said, I found exactly the opposite true on my day hikes where the pack wasn't as full. Having a large zippered opening did indeed allow me to reach gear at the bottom of my pack without too much trouble. I was able to get out a jacket, snacks, and even my heavy down coat without having gear fall all over. I think the difference is definitely due to the way items were packed and the shuffle room that I had when the pack was not stuffed to the brim with necessary cold weather gear.

I found that during my multi-night outings the best place for my hydration bladder was in the air space between the pack and my back as opposed to inside the main compartment. I did feel a bit cooler as the colder water was against my back, but this also provided a bit of extra cushion against the overstuffed pack. On the flip side, having it in the main compartment proved to be best during day hikes. My back was able to breathe more, and the pack just felt more comfortable during the whole trip. However, having the ability to change whenever I want is definitely a plus, and something that I would have considered if I were purchasing this in a retail store.

I have not had any additional problems with any of the zippers during this testing phase. I feel that I might have been a bit more gentle than normal, but it was nothing that was overly difficult. It was more of a mindset since I had experienced problems in the beginning. I'll continue to keep an eye on this throughout the testing phase, but I'm inclined to think it was just a fluke based on the experiences I've had to date.

I'm still very pleased with the operation of the Osprey Atmos 35, and to date I have not found anything I haven't liked.

Long Term Report: January 26, 2010

Field Conditions:

During this testing phase I was able to get an additional 3 days worth of use out of the Osprey Atmos 35. Due to the weather all three uses were on day hikes in 2 different recreational areas in Western Kentucky.  Elevation here is roughly 400 ft (120 m) with little change in terrain, some rocky sections, but mostly a lot of mud and muck this time. Temperatures that I experienced during the outings ranged from 35 - 55 F (2 - 13 C). All three trips were during overcast skies, but there was no precipitation at all. In total, over the life of the test I've used this pack for seven to eight days of use.


During this testing phase I found that I much prefer this pack as a day hiking pack during the winter months. This may change during the spring & summer, but trying to pack the cold weather gear I needed for an overnight into this pack just wasn't feasible this testing phase. I didn't have enough room and I felt like the pack was bulging at the seams. I ended up having to take a different pack for my overnight trip.

However, as I already mentioned, using this as a daypack  served me well. Because it rides so nicely on my shoulders and hips, I was more than happy to take it with me. I was able to pack a good amount of layerable clothing into this pack and still not feel like I was carrying too much, or feel like my pack was overstuffed. Having the ability to take a couple of different sweaters, jackets, a heavy coat for the times I stopped completely (lunch), and over-pants made layering a breeze. Also I found that the zipper did indeed continue to work better when the pack wasn't stuffed and I was able access clothing easily. I found out the definite advantage to this was my comfort level and ability to retain heat. Because I wasn't digging around in my pack looking for clothing, I lost less heat when I needed to stop and don or doff layers. Such a nice change from times I was freezing while digging in my other packs.

The fit of the Atmos 35 on my back continued to be extremely comfortable. While it felt good even when overstuffed, it was all that much more comfortable on days when it wasn't packed with heavy gear. I didn't find myself fiddling with the straps as much trying to shift weight, nor did I feel the usual pain in my hips or in the area of my clavicle. The padding continued to remain intact, which was something I was worried about after seeing the honeycomb design. My zipper problems seem to have all but vanished. Only once during the testing phase did I notice a problem, and this was due to my snagging the zipper on some fabric inside the pack.

In closing, I continue to remain very pleased with the quality, design, usability, and  comfort of the Osprey Atmos 35. I have found that it lives up to the quality that I've come to expect in the Osprey packs that I already had. It will definitely be one of the front line packs in my arsenal. I'd like to thank and Osprey for allowing me to participate in this test.

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